Physics I Final

True!

T/F: every object, including the human body, can radiate + absorb radiation. That process will continue until the object reaches thermal equilibrium with its environment

B. increase pan bottom thickness

If cooking is done using an aluminum pan over an electric burner, which of the following will not promote the rate of heat flow from burner to food? A. increase pan bottom area B. increase pan bottom thickness C. increase burner temperature D. decrease height of pan sides

Decrease! Bernoulli's principle

If you have a fluid speeding up, what happens to the pressure?

Because of the unusual behavior of water! Water at and below 4C starts to exand, so it rises to the top before it freezes. At 0, when it begins to freeze it stays on top, and ice begins to form

Why do lakes freeze from the top down?

If a car is going REALLY fast, the speed of the air above is way faster than the speed of the air below. That means that pressure below >> pressure above, so the car is in danger of flipping. Spoilers prevent the car from flipping by slowing the speed of the air above the car without having too much drag (reduce the speed above to push the car down)

Why do some cars have spoilers?

2 reasons: 1. Need to reduce speed as landing 2. Reducing speed also reduces the lift! So trying to increase the area to keep up lift while slowing down

Why do the flaps come up when an airplane is trying to land?

Convection! The sun delivers the same amount of heat per unit mass to both sand and water. But! The specific heat of sand << specific heat of water. Sand transfers heat to air above sand, either by radiation or conduction. Water transfers heat to air above water, either by radiation or conduction. The air above the water, though, won't be as hot as the air above the sand, because of the specific heat differential, so convection begins. Colder air moves towards the shore to replace hot air... feels like a breeze coming off of the water.

Why do you feel a breeze on a hot day at the beach?

Air is moving inside of the shower, so speed increase causes pressure to decrease. This causes net force from outside pushing in, which pushes the curtain towards you

Why does a shower curtain pull in when you shower?

Water is in free fall, so speeding up. If v is increasing, cross-sectional area, and therefore width, must decrease (volume per unit time can't change!) This is equation of continuity

Why does a stream of water narrow as it falls from the faucet?

Because of the unusual behavior of water! Water at and below 4C starts to exand, so it rises to the top before it freezes. Water that isn't yet frozen sinks to the bottom, and allows marine life to live.

Why is it possible for fish to live at the bottom of a lake?

Due to high specific heat of water and convection! Water of the pacific ocean releases huge amount of heat into the air above the water. Why is this different than the east coast? Well, the same heat release is happening, but west is milder because the prevailing winds push air towards the land, while on the east coast, they push air away from the land

Why is the west-coast climate more mild during the winter?

Because of static equilibrium! If pressure wasn't the same, there would be a net force, and the fluid would be in motion

Why must all points at the same depth be at the same pressure?

If two automobiles collide, they usually do not stick together. Does this mean the collision is elastic? (b) Explain why a head-on collision is likely to be more dangerous than other types of collisions.

A greater portion of the incident kinetic energy is transformed to other forms of energy in a head-on collision than in a glancing collision. Thus, the expectation of damage to passengers is greatest in head-on collisions.

c. experiences no change in internal energy due to energy transfer by heat

A gas that expands adiabatically a. experiences no temperature change. b. has no work done on it and does no work. c. experiences no change in internal energy due to energy transfer by heat d. experiences increase in temperature.

b). the same as ladybug's.

A ladybug sits at the outer edge of a merry-go-round, and a gentleman bug sits halfway between her and axis of rotation (see a figure). The merry-go-round makes a complete revolution once each second. The gentleman bug's angular speed is... a). half the ladybug's. b). the same as ladybug's. c). twice the ladybug's. d). impossible to determine.

a. the force of friction between the crate and the truck

A large crate of mass m is placed on the back of a truck but not tied down. As the truck accelerates forward with acceleration a, the crate remains at rest relative to truck. What force causes the crate to accelerate? a. the force of friction between the crate and the truck b. the force of gravity c. the "ma" force d. the normal force

a). 1/2

A racetrack is constructed such that two arcs of radius 80m at A and 40m at B are joined by two stretches of straight track. In a particular trial run, a driver travels at a constant speed of 50m/s for one complete lap. 2. The ratio of the centripetal acceleration at A to that at B is... a). 1/2 b). 1/4 c). 2 d). 4 e). the centripetal acceleration is zero at both points

b). B

A racetrack is constructed such that two arcs of radius 80m at A and 40m at B are joined by two stretches of straight track. In a particular trial run, a driver travels at a constant speed of 50m/s for one complete lap. 3. The angular speed is greatest at... a). A b). B c). It is equal at both A and B

1

A rider in a "barrel of fun" finds herself stuck with her back to the wall. Which diagram correctly shows the forces acting on her?

c). 1 rad, 5 rad

A rigid body is rotating counterclockwise about a fixed axis. Each of the following pairs of quantities represents an initial angular position and a final angular position of the rigid body. Which of the sets can occur only if the rigid body rotates through more than 180 degrees? a). 3 rad, 6 rad b). -1 rad, 1 rad c). 1 rad, 5 rad

d) (a) or (b) occurred, but not (c).

A violation of the second law of thermodynamics would occur if a) a ball lying on the ground started to bounce. b) transfer of energy by heat moved energy from an object at low temperature to an object at a higher temperature. c) a refrigerator heated the air in the room in which the refrigerator is located. any of the above occurred. d) (a) or (b) occurred, but not (c).

It does not matter, her speed would be the same for each slide.

A young girl wishes to select on of the frictionless playground slides illustrated below to give her the greatest possible speed when she reaches the bottom of the side. Which of the slides should she chose?

b. 8.8

An automobile engine operates with an overall efficiency of 12%. How much energy is delivered as waste heat (in gallons of gasoline) for each 10 gallons of fuel burned? a. 1.2 b. 8.8 c. 6.5 d. 4.7 e. 7.5

e). one-fourth as large as the gravitational force exerted by the planet on moon 1

A planet has two moons with identical mass. Moon 1 is in a circular orbit of radius r. Moon 2 is in a circular orbit of radius 2r. The magnitude of the gravitational force exerted by the planet on Moon 2 is... a). 4 times as large b). twice as large c). the same d). half as large e). one-fourth as large as the gravitational force exerted by the planet on moon 1

B. convection.

Areas near a cold ocean or other cold body of water often experience a 'sea breeze' during the late morning, particularly on warm, sunny days. The process of energy transfer most directly associated with the development of the sea breeze is A. conduction. B. convection. C. radiation. D. none of the above

b). the same as Chuck's

Andrea and Chuck are riding on a merry-go-round. Andrea rides on a horse at the outer rim of the circular platform, twice as far from the center of the circular platform as Chuck, who rides on an inner horse. When the merry-go-round is rotating at a constant angular speed, Andrea's angular speed is... a). twice Chuck's b). the same as Chuck's c). half of Chuck's d). impossible to determine

e. 1000

Answer the following question without using an online converter of units. In General Chemistry class you learned that the density of water at 4 ∘C is close to 1 g/cm3 (or 1 g/mL). Density of water in kg/m3 is closest to: a. 0.01 b. 10 c. 100 d. 0.001 e. 1000 f. 10000 g. 0.1

False

Car that is moving on a circle with a constant speed has no acceleration.

B. energy conservation in moving fluids.

Complete the following statement: Bernoulli's principle is a statement of A. momentum conservation in moving fluids. B. energy conservation in moving fluids. C. mechanical equilibrium in fluids. D. hydrostatic equilibrium.

C. that is equal to the weight of the fluid displaced by the object.

Complete the following statement: When an object is placed in a fluid, a buoyant force is exerted on it that is directed upward with a magnitude A. that is greater than the force of gravity on the object. B. that is greater than the weight of the fluid displaced by the object. C. that is equal to the weight of the fluid displaced by the object. D. that is less than the weight of the fluid displaced by the object. E. that is equal to the force of gravity on the object.

NO

Does pressure depend on shape of container?

Water flows faster in the narrow part and slower the wide part because A1V1 = A2V2. Area increases, so speed must decrease.

Does water flow faster in the narrow part of a river, or the wide part? Why?

b. a, c, b, d

By visual inspection, order the PV diagrams shown in the figure from the most negative work done on the system to the most positive work done on the system

Increasing number of molecules per unit volume in the container Increasing the average translational kinetic energy of the molecules

How can you increase pressure? (2 ways)

ΔU = Q + W, so Q = ΔU - W

How do we express internal energy if P is constant?

CONVECTION! The radiator warms the air in the lower region of the room. The warm air is less dense, so it rises to the ceiling. The denser, cooler air sinks. A continuous air current pattern is set up as shown.

How does a radiator work?

Through radiation

How does fire warm your hands?

All 3 - conduction, convection, and radiation!

How does the human body transfer heat?

b. constant pressure process.

For the same temperature increase in a system, the change in entropy, ΔS, is largest in a reversible a. constant volume process. b. constant pressure process. c. adiabatic process. d. process in which no heat is transferred. e. process in which no work is performed.

Instantaneous acceleration: the instantaneous acceleration of an object at a given time equals the slope of the tangent line to the velocity vs. time graph at that time. In the special case where the velocity vs. time graph of an object's motion is a straight line, the instantaneous acceleration of the object at any point is equal to its average acceleration

Given a graph, how would you identify instantaneous acceleration?

False

If you are sliding down the sloped surface, the normal force on you is equal to your weight. True False

b). 0 Joules of work.

If you displace a bucket of water weighing 100 N horizontally by 10 m your hand does... a). -100 Joules of work. b). 0 Joules of work. c). -1000 Joules of work d). 1000 Joules of work. e). 100 Joules of work.

Vrms = 1/(M)^1/2, so the lighter particle must move faster at a given temperature. VH2/VO2 = (MO2/MH2)^1/2 = (32/2)^1/2 = 4

In a gas with H and O molecules in thermal equilibrium, which ones move faster, and by which factor?

C. Quadruples.

If the speed of a molecule in a container doubles (other things remaining the same), the average pressure that this molecule exerts on the container wall A. Remains the same B. Doubles C. Quadruples. D. It is impossible to determine.

More!

Is a Carnot engine more or less efficient than real life engines?

A. The internal energy decreases.

Let's say that an ideal gas decreases in temperature, but that its volume remains constant during this process. What happens to its internal energy in this case? A. The internal energy decreases. B. The internal energy increases. C. The internal energy remains constant. D. It cannot be determined whether it will increase, decrease, or remain the same.

A: x is negative, y is positive B: x is positive, y is negative A + B: both x and y are negative

The figure shows two vectors lying in the xy-plane. Determine the signs of the x and y components of A, B, and A + B

d). depends on the reference configuration for zero potential energy.

The gravitational potential energy of a system a). is always zero. b). is always positive. c). is always negative. d). depends on the reference configuration for zero potential energy.

False

The instantaneous acceleration is the slope of the tangent to the displacement vs time graph. True False

b). The one with the highest mass.

Three different-mass balls are launched from the top of a building each at different angles of elevation. Each particle has the same initial kinetic energy. Which particle has the greatest kinetic energy just as it impacts with the ground? a). The one launched at the highest angle of elevation. b). The one with the highest mass. c). The one with the lowest mass. d). They all will have the same kinetic energy on impact.

d). All three balls strike the ground at the same speed

Three identical balls are thrown from the top of a building, all with the same initial speed. The first ball is thrown horizontally, the second at some angle above the horizontal, and the third at some angle below the horizontal. Neglecting air resistance, rank the speeds of the balls as they reach the ground, from fastest to slowest. a). 1, 2, 3 b). 2, 1, 3 c). 3, 1, 2 d). All three balls strike the ground at the same speed

d). not enough information given to tell

Object 1 has more kinetic energy than Object 2. How do the magnitudes of their momenta compare? a). p1=p2 b). p1 > p2 c). p1 < p2 d). not enough information given to tell

Objects are in thermal contact if energy can be exchanged between them

Objects are in thermal contact if...

a. False b. True c. True

True or false? a. A car must always have an acceleration in the same direction as its velocity b. It's possible for a slowing car to have a positive acceleration c. An object with constant nonzero acceleration can never stop and remain at rest

Light particles are moving faster, so overall KE is the same (mass decreases, but v increases, and T is kept constant). P = 2/3(N/V)(1/2 * mv^2) Pressure is directly proportional to the average KE and # of moles

Pressure is the same, for same amount of particles, in a closed container, regardless of if particles are heavy or light. Why?

Your physical education teacher throws you a tennis ball at a certain velocity, and you catch it. You are now given the following choice: The teacher can throw you a medicine ball (which is much more massive than the tennis ball) with the same velocity, the same momentum, or the same kinetic energy as the tennis ball. Which option would you choose in order to make the easiest catch, and why?

Same momentum (slowest speed/velocity)

Shortest = ultraviolet Longest = infrared

Shortest/longest wavelengths?

a. 4 b. 16 c. 64

Stars A and B have the same temperature, but star A has twice the radius of star B. a. What is the ratio of star A's power output to star B's output due to electromagnetic radiation? b. Repeat the question if the stars have the same radius, but star A has twice the absolute temperature of star B c. What's the ratio if star A has both twice the radius and twice the absolute temperature of star B?

a). twice Chuck's

When the merry-go-round below is rotating at a constant angular speed, Andrea's tangential speed is... Andrea and Chuck are riding on a merry-go-round. Andrea rides on a horse at the outer rim of the circular platform, twice as far from the center of the circular platform as Chuck, who rides on an inner horse. a). twice Chuck's b). the same as Chuck's c). half of Chuck's d). impossible to determine

d). Yes, it is possible.

The center of gravity is a useful point at which to balance an object. For instance, a ruler can be balanced by placing its center on your finger. Is it possible for the center of gravity of an object to be located at a point where no material exists to balance the object? a). no, never b). only for very unsymmetrical objects c). It is possible in theory, but no objects have been found for which this occurs. d). Yes, it is possible.

A skater is standing on a frictionless ice rink. Her friend throws a Frisbee straight at her. In which of the following cases is the largest momentum transferred to the skater? (a) The skater catches the Frisbee and holds onto it. (b) The skater catches the Frisbee momentarily, but then drops it vertically downward. (c) The skater catches the Frisbee, hold it momentarily, and throws it back to her friend.

Since the total momentum of the skater-Frisbee system is conserved, the momentum transferred to the skater equals the magnitude of the change in the Frisbee's momentum. This is greatest when the skater throws the Frisbee back after catching it.

Perfect reflector, lighter the object smaller the e

e = 0

in most circumstances, the normal force acting on an object and the force of static friction do no work on the object. however, the reason that the work is zero is different for the two cases. explain why each does zero work

normal force is perpendicular to direction of motion; there is no change in kinetic energy for static friction, since the object remains at rest

when a punter kicks a football, is he doing any work on the ball while the toe of his foot is in contact with it? is he doing any work on the ball after it loses contact with his toe? are any forces doing work on the ball white it is in flight?

punter is only doing work when in contact with the ball gravity and air resistance are also doing work on the ball

By blowing above, we create a 'lift' force. Can be explained by Bernoulli's principle: P + 1/2pv^2 + pgy = constant Because speed of air above increases, pressure above must decrease. This means that there is a net force from the pressure below pushing up!

Why does paper flip up if you blow above it?

Because it's thermal conductivity value is relatively low (see: table, it's about 0.2 vs. 238 for aluminum, e.g.)

Why does rubber make a good insulator?

Because the equation for efficeincy of a heat pump is: COP = |Qh|/W =< Th/(Th - Tc) So the larger the denominator, the less efficient the system

Why is it better to use heat pumps in climates where there is not such a large difference between outside and inside temperatures?

Because e = benefit/cost = W/Qh = Qh - Qc / Qh = 1 - Qc/Qh So to have e = 100%, Qc must be 0. This is impossible, because of the second law of thermo. Entropy must always increase!

Why is it impossible for. a heat engine to have an efficiency of 100%?

If you sum the thermal resistance of those layers, including the air between, you will end up with a larger R value, and therefore smaller total heat transfer (heat leaves your body slower, cold enters your body slower)

Why should you layer on a cold day?

c. a longer time than an identical ice cube exposed to air at room temperature

Will an ice cube wrapped in a wool blanket remain frozen for: a. less time b. the same length of time c. a longer time than an identical ice cube exposed to air at room temperature

during a stress test of the cardiovascular system, a patient walks and runs on a treadmill. a) is the energy expended by the patient equivalent to the energy of walking and running on the ground? b) if the treadmill is tilted upward, what effects does this have?

a) effects are the same (except for air resistance) b) effect of running uphill

b). Starting at the time of collision, the door exerts a leftward force on you.

You are a passenger in a car and not wearing your seat belt. Without increasing or decreasing its speed, the car makes a sharp left turn, and you find yourself colliding with the right-hand door. Which is the correct analysis of the situation? a). Before and after the collision, there is a rightward force pushing you into the door. b). Starting at the time of collision, the door exerts a leftward force on you. c). both of the above. d). neither of the above

c. second Newton's law

You are holding your physics book in a palm of your hand. A normal upward force that your hand exerts on the book is equal to the weight of the book because of: a. because the book is in free-fall motion b. third Newton's law c. second Newton's law

in a race like the indianapolis​ 500, a driver circles the track counterclockwise and feels his head pulled to one shoulder. to relieve his neck muscles from having to hold his head erect, the driver fastens a strap to one wall of the car and the other to his helmet. the length of his strap is adjusted to keep his head vertical. which shoulder does his head tend to lean towards?

right/outside of curve

A. the liquid water

You have 1 kg of liquid water and 1 kg of steam. If you want to increase the temperature of both of them by 10 oC, which would require more added energy? A. the liquid water B. the steam C. They both require the same amount of energy to be warmed 10 oC. D. It cannot be determined because it depends on the actual temperature of the water and steam as well as the pressure.

a. They move toward each other

You observe two helium balloons floating next to each other at the ends of strings secured to a table. The facing surfaces of the balloons are separated by 1-2 cm. You blow through the opening between the balloons. What happens to the balloons? a. They move toward each other b. They move away from each other c. They are unaffected

Δ Velocity

the area under an acceleration curve represents the change in velocity. In other words, the area under the acceleration graph for a certain time interval is equal to the change in velocity during that time interval

Distance

the area under the speed vs. time curve is equal to the distance traveled by an object. If the shape of the graph can be broken into simple geometric shapes, the total area under the line can be calculated by adding the areas of those shapes

Displacement

the area under the velocity vs. time curve is equal to the displacement of the object. If the shape of the graph can be broken into simple geometric shapes, the total area under the line can be calculated by adding the areas of those shapes

Instantaneous speed

the magnitude of the instantaneous velocity is defined as the instantaneous speed

Instantaneous velocity

the slope of the tangent line to the position vs. time graph is defined as the instantaneous velocity at that time

d. speeds up.

An object is held in place by friction on an inclined surface. The angle of inclination is increased until the object starts moving. If the surface is kept at this angle, the object a. moves at uniform speed. b. slows down. c. none of the above. d. speeds up.

b. at the peak of its path

As a projectile moves in its parabolic path, the velocity and acceleration vectors are perpendicular to each other... a. everywhere along the projectile's path b. at the peak of its path c. nowhere along its path d. not enough information is given

c. nowhere

As a projectile thrown upward at a non-vertical angle moves in a parabolic path, at what point along its path are the velocity and acceleration vectors for the projectile parallel to each other? a. at the launch point b. at the point just before the projectile lands c. nowhere d. at the highest point

Why do astronauts feel weightless?

First, gravity is the centripetal force that keeps the astronauts and their spacecraft in orbit around the Earth, so the astronauts aren't beyond gravity's influence. Second, weight is the magnitude of the gravitational force, so astronauts inEarth orbit have weight, although it's lower than on Earth's surface. Because they are freely falling around the Earth along with their spacecraft environment, gravity doesn't press them against the cabin's walls or floor, giving rise to the feeling of weightlessness. The same feeling of weightlessness would occur in a freely falling elevator.

d). the sum of the torques about any point must equal zero

For a body to be equilibrium under the combined action of several forces: a). all the forces must be applied at the same point b). all of the forces are composed of pairs of equal and opposite forces c). any two of these forces must be balanced by a third d). the sum of the torques about any point must equal zero

B. lower than in the non-constricted region.

The pressure in the constricted region of artery shown in Figure 9.36 is A. higher than in the non-constricted region. B. lower than in the non-constricted region. C. same as in the non-constricted region. D. can not be determined from the information given.

he root-mean-square speed is the measure of the speed of particles in a gas, defined as the square root of the average velocity-squared of the molecules in a gas.

What is RMS speed?

c). the sum of the kinetic energy and the potential energy.

Which of the following is (are) conserved in an isolated system? a). the potential energy alone. b). both the potential energy and the kinetic energy c). the sum of the kinetic energy and the potential energy. d). the kinetic energy alone.

b. Δs = 0

Which of the following is true for the entropy change of a system that undergoes a reversible, adiabatic process? a. Δs < 0 b. Δs = 0 c. Δs > 0

b. An object moving with a constant velocity

Which of the following objects can't be accelerating? a. An object moving with a constant speed b. An object moving with a constant velocity c. An object moving along a curve

B. The buoyant force depends on the volume of the liquid displaced.

Which one of the following statements concerning the buoyant force on an object submerged in a liquid is true? A. The buoyant force will increase with depth if the liquid is incompressible. B. The buoyant force depends on the volume of the liquid displaced. C. The buoyant force depends on the weight of the object. D. The buoyant force depends on the mass of the object. E. The buoyant force is independent of the density of the liquid.

e). The value of G is the same everywhere in the universe, but the value of g is not.

Which one of the following statements concerning the two "gravitational constants" G, the universal gravitational constant, and g the magnitude of the acceleration due to gravity is true? a). The values of g and G depend on location. b). The values of g and G do not depend on location. c). The value of g is the same everywhere in the universe, but the value of G is not. d). The values of g and G are equal on the surface of any planet, but in general, vary with location in the universe. e). The value of G is the same everywhere in the universe, but the value of g is not.

Area decreases, so speed increases (A1V1 = A2V2). Speed increase causes pressure to decrease. The change in pressure is not good for the heart

Why are deposits in the aorta bad? Explain using Bernoulli's principle.

lol sorry

See: book for quick quiz #3 (page 34)

e. remain constant

A tennis player tosses a ball straight up. While the ball is in free fall, does its acceleration (a) increase, (b) decrease, (c) increase and then decrease, (d) decrease and then increase, or (e) remain constant?

b. exactly 9.8 m/s2

A ball is dropped from the top of the tower and is in the free fall motion. Its downward acceleration is zero a. larger than 9.8 m/s2 b. exactly 9.8 m/s2 c. smaller than 9.8 m/s2

False

A car traveling at constant speed on a straight road is not in equilibrium. True False

a). perfectly inelastic b). inelastic c). inelastic

A skater is using very low-friction rollerblades. A friend throws a frisbee at her, on the straight line along which she is coasting. Describe each of the following events as an elastic, inelastic, or perfectly inelastic collision between the skater and the frisbee. a). She catches the frisbee and holds it b). She tries to catch the Frisbee, but it bounces off her hands and falls to the ground in front of her c). She catches the Frisbee and immediately throws it back with the same speed (relative to the ground) to her friend

Vertical distance: a. increase Difference in velocities: c. stay the same

A skydiver jumps out of a hover helicopter. A few seconds later, another skydiver jumps out, so they both fall along the same vertical line relative to the helicopter: both skydivers fall with the same acceleration. Does the vertical distance between them a. increase, b. decrease, or c. stay the same? Does the difference in their velocities a. increase, b. decrease, or c. stay the same? (Assume g is constant)

h/2

A spring loaded gun can fire a projectile to a height h if it is fired straight up. If the same gun is pointed at an angle of 45° from the vertical, what maximum height can now be reached by the projectile?

c. decrease and then increase

A tennis player tosses a ball straight up. As it travels through the air, does its speed a. increase, b. decrease, c. decrease and then increase, d. increase and then decrease, or e. remain the same?

D. 718

According to Figure 11.3 how many calories are required to change one gram of 0oC ice to 100oC steam? A. 118 B. 318 C. 518 D. 718 E. 918

False

All objects dropped near Earth's surface simultaneously from the same height will hit the ground at the same time. True False

a. The object's acceleration is in the same direction as the net force that acts upon it.

An object accelerates when it experiences a non-zero net force. Which of the following statements is always true? a. The object's acceleration is in the same direction as the net force that acts upon it. b. The object's velocity increases. c. The object's velocity is in the same direction as its acceleration. d. The object moves in the direction of the net force.

b. either smaller than or equal to the distance it traveled.

An object goes from one point in space to another. After it arrives at its destination, its displacement is: a. always smaller than the distance it traveled. b. either smaller than or equal to the distance it traveled. c. always greater than the distance it traveled. d. either greater than or equal to the distance it traveled. e. always equal to the distance it traveled. f. either smaller or larger than the distance it traveled.

A more ordinary example of conservation of momentum than a rocket ship occurs in a kitchen dish-washing machine. In this device, water at high pressure is forced out of small holes on the spray arms. Use conservation of momentum to explain why the arms rotate, directing water to all dishes.

As the water is forced out of hole in the arm, the arm imparts a horizontal impulse to the water. The water then exerts an equal and opposite impulse on the spray arm, causing the spray arm to rotate in the direction opposite that of the spray.

B

At a particular instant, a stationary observer on the ground sees a package falling with speed v1 at an angle to the vertical. To a pilot flying horizontally at constant speed relative to the ground, the package appears to be falling vertically with a speed v2 at that instant. What is the speed of the pilot relative to the ground?

c. no different than on a low pressure day

Atmospheric pressure varies from day to day. The level of a floating ship on a high-pressure day is: a. higher b. lower c. no different than on a low pressure day

c). They have the same kinetic energy

Bob, of mass m, drops from a tree limb at the same time that Esther, also of mass m, begins her descent down a frictionless slide. If they both start at the same height above the ground, which of the following is true about their kinetic energies as they reach the ground? a). Bob's kinetic energy is greater than Esther's b). Esther's kinetic energy is greater than Bob's c). They have the same kinetic energy d). The answer depends on the shape of the slide

Perfect emitter/absorber, e = 1

Blackbody

A. the narrow part.

Blood flows through a coronary artery that is partially blocked by deposits along the artery wall. Through which part of the artery is the flow speed largest? A. the narrow part. B. the wide part. C. the flow speed is the same in both parts. D. do not have enough information.

One commentator remarked that the force of the explosion at the Twin Towers of the World Trade Center was strong enough to blow glass and parts of the steel structure to small fragments. Yet the television coverage showed thousands of sheets of paper floating down, many still intact. Explain how that could be.

Both the paper and the steel/glass structures experience the same Impulse(momentum) from the force of explosion. Due to the elasticity, paper experiences the force of explosion for a longer period of time which reduces the magnitude of force experienced. The steel/glass structure feels the full force because it has limited elasticity and cannot move with the force of explosion. Therefore the many remain intact.

C. C

By adding 25 kJ to solid material A, 4.0 kg will melt. By adding 50 kJ to solid material B, 6.0 kg will melt. Solid material C requires 30 kJ to melt 3.0 kg. Which of these materials, if any, has the largest value for the heat of fusion? A. A B. B C. C D. A=B

c. the net force on the car is zero.

Consider a car at rest. We can conclude that the downward gravitational pull on the car and the upward contact force of the ground on it are equal and opposite because a. the two forces form an action-reaction pair. b. do not have enough information to answer this question. c. the net force on the car is zero. d. neither of the above.

a. larger than the weight of the person

Consider a person standing in an elevator that is accelerated upward. The upward normal force N exerted by the elevator floor on the person is a. larger than the weight of the person b. smaller than the weight of the person. c. identical to the weight of the person. d. zero.

b). -1 rad, 1 rad The object arrives at the final position with the same angular speed W(Af) = W(Bf) = W (Cf) = 5 rad (for instant) Wf = Wi + (alpha x time) Acceleration (Alpha) = (Wf - Wi)/timeA (5-3)/t = 2/t B. (5 - (-1)/t = 6/t C. (5-1)/t = 4/t The correct answer is B. -1 rad, 1 rad

Consider again the pairs of angular positions below (rigid object). If the object starts from rest at the initial angular position, moves counterclockwise with constant angular acceleration, and arrives at the final angular position with the same angular speed in all three cases, for which choice is the angular acceleration the highest? a). 3 rad, 6 rad b). -1 rad, 1 rad c). 1 rad, 5 rad

B. It will contract slightly (its volume will decrease).

Consider an amount of water freshly melted from snow in a pan and that the water has a temperature of 1°C. What will happen to the water as its temperature is increased to 3°C? A. It will expand slightly (its volume will increase). B. It will contract slightly (its volume will decrease). C. Its volume will not change. D. Its mass will decrease.

d). it is larger (by 2 times) KE = 0.5mv² We don't know velocities, but we know momentum of both carts are equal If momentums of both are equal, then SPEED of light cart must be twice that of heavy cart. Light Cart: 0.5mv² ---- 0.5(m)((2v)²) = 2mv²Heavy Cart: 0.5mv² ----- 0.5(2m)(v²) = 1mv²

Consider two carts, of masses m and 2m, at rest on a track with negligible friction . If you push first one cart for 3s and then the other for the same length of time, exerting equal forces on each, how does the kinetic energy of the light cart compare to the kinetic energy of the heavy cart? a). can not be determined from the information given. b). It is smaller c). They are equal. d). It is larger.

C. 1 g/cm3

Density of water at 0o C is: A. 1 kg/m3 B. 1 g/m3 C. 1 g/cm3 D. 1kg/cm3

While conduction is the transfer of heat energy by direct contact, convection is the movement of heat by actual motion of matter (due to different temperatures); radiation is the transfer of energy with the help of electromagnetic waves.

Differentiate between conduction, convection, and radiation

Internal energy, U, is the energy associated with the microscopic energy of the system Heat, Q, is the transfer of energy between a system and its environment because of a temperature difference between them

Differentiate between internal energy and heat

d). all of the above.

Effectiveness of the force F in opening a door in Figure 8.1 is determine by... a). the force magnitude. b). the position of the application of the force. c). the angle at which the force is applied. d). all of the above.

False

Efficiency of a heat engine can be as large as 100% True False

Displacement: the area under the velocity vs. time curve is equal to the displacement of the object. If the shape of the graph can be broken into simple geometric shapes, the total area under the line can be calculated by adding the areas of those shapes

Given a graph, how would you identify displacement?

B. 1/2.

Equal masses of hydrogen and helium gas are at the same temperature in vessels of equal volume. The atomic mass of helium is four times that of hydrogen. If the total mass of both gases is the same, the ratio of the pressure of helium (He) to that of hydrogen (H2) is A. 1/4. B. 1/2. C. 1. D. 2. E. 4.

False

Equation f s = μ s N where N is the normal force is used to calculate force of static friction fs . True False

b). relative velocities before and after collision.

Equation 6.14 in the textbook describes: a). kinetic energies before and after collision. b). relative velocities before and after collision. c). momenta before and after collision. d). none of the above.

Distance: the area under the speed vs. time curve is equal to the distance traveled by an object. If the shape of the graph can be broken into simple geometric shapes, the total area under the line can be calculated by adding the areas of those shapes

Given a graph, how would you identify distance?

The work done on the gas that takes it from some initial state to some final state is equal in magnitude to the area under the curve on a PV diagram

Given a PV diagram, how can we determine the magnitude of the work done on a gas?

Instantaneous speed: the magnitude of the instantaneous velocity is defined as the instantaneous speed

Given a graph, how would you find instantaneous speed?

Instantaneous velocity: the slope of the tangent line to the position vs. time graph is defined as the instantaneous velocity at that time

Given a graph, how would you find instantaneous velocity?

A heat engine is a machine that converts thermal energy into mechanical energy Heat engines are the devices which convert the thermal energy into mechanical work, while heat pumps transfer heat energy from low temperature to high temperature. Work is SUPPLIED in order to make this happen Heat pump is heat engine in reverse

Heat pump vs. heat engine?

A. Isovolumetric B. Adiabatic C. Isothermal D. Isobaric

Identify the paths A, B, C, and D in the figure as isobaric, isothermal, isovolumetric, or adiabatic. For path B, Q = 0

In most situations we have encountered in this chapter, frictional forces tend to reduce the KE of an object. However, frictional forces can sometimes increase an object's KE. Describe a few situations in which friction causes an increase in KE.

If a crate is located on the bed of a truck, and the truck accelerates, the friction force exerted on the crate causes it to undergo the same acceleration as the truck, assuming that the crate doesn't slip. Another example is a car that accelerates because of the frictional forces between the road surface and its tires. This force is in the direction of the motion of the car and produces an increase in the car's kinetic energy.

b). r

If a force F acts at a pivot (or at an axis of rotation), torque that F exerts on a rotating object is zero. Which of the three quantities in the formula τ = r F sin ⁡ θ is zero in this situation? a). F b). r c). θ d). both F and r are zero.

B. the same as the force required to hold brick A in place.

Imagine holding two identical bricks under the water. Brick A is just beneath the surface of the water, while brick B is at greater depth. The force needed to hold brick B in place is A. larger than the force required to hold brick A in place. B. the same as the force required to hold brick A in place. C. smaller than the force required to hold brick A in place. D. can not be deduced from information given.

a). the objects must have momenta with the same magnitude but opposite directions

In a perfectly inelastic one-dimensional collision between two objects, what condition alone is necessary so that all of the original kinetic energy of the system is gone after the collision? a). the objects must have momenta with the same magnitude but opposite directions b). the objects must have the same mass c). the objects must have the same velocity d). the objects must have the same speed, with velocity vectors in opposite directions

c. the elevator accelerates in an upward direction.

In an elevator, the force that the floor pushes on you in the upward direction (i.e. the normal force) will be larger than your weight if a. the elevator accelerates in a downward direction. b. the elevator is at rest. c. the elevator accelerates in an upward direction. d. the elevator moves at the constant velocity.

W = -Q, because ΔU = 0 (ΔT = 0) Work: W = -nRTln(Vf/Vi)

In an isothermal process, what is the first law of thermo? How do we calculate work?

C. be in thermal equilibrium.

In order for two objects to have the same temperature, they must A. be in thermal contact with each other. B. have the same relative "hotness" or "coldness" when touched. C. be in thermal equilibrium. D. have all of the properties listed above. E. have only properties (b) and (c) above.

True

In ideal gas the molecules interact only during the elastic collisions but otherwise do not exert any forces on each other. True False

d). the area under the curve.

In the case of a force varying with position, what feature of the graph of force vs. position represents the work done during a displacement? a). the beginning force times the total displacement b). none of the above. c). the maximum force times the maximum position d). the area under the curve.

Positive if work is done on the system Negative if work is done by the system

In the first law of thermo: When is w positive? When is it negative?

Positive if temperature increases Negative if temperature decreases

In the first law of thermo: When is ΔU positive? When is it negative?

Positive if energy is transferred to the system by heat Negative if energy is transferred out of the system by heat

In the first law of thermo: When is q positive? When is it negative?

False

In the plane polar coordinate system a point can be described with the polar coordinates r and θ. Coordinate θ is the angle measured clockwise from the positive x-axis. True False

A. when the person is lying down on the floor

In which of the following cases would the maximum "contact pressure" from the floor on a person be the least? A. when the person is lying down on the floor B. when the person is sitting on the floor C. when the person is standing on the floor D. when the person is standing on their tip-toes on the floor

A ball of clay of mass M is thrown with a speed V against a brick wall. The clay sticks to the wall and stops. Is the principle of conservation of momentum violated in this example?

Initially, the clay has momentum directed toward the wall. When it collides and sticks to the wall, neither the clay nor the wall appears to have any momentum. Thus, it is tempting to (wrongfully) conclude that momentum is not conserved. However, the "lost" momentum is actually imparted to the wall and Earth, causing both to move. Because of Earth's enormous mass, its recoil speed is too small to detect.

D. Yes, in some cases a substance's temperature will change when energy is added to the substance. In other cases, the substance's temperature will not change when energy is added.

Is it possible to add energy to an isolated substance and not have the substance's temperature change? A. No, the subtsance's temperature will always go up when energy is added to it. B. No, the substance's temperature will sometimes go up and sometimes go down when energy is added, but it will always change. C. Yes, temperature change is not a function of energy added to a substance. D. Yes, in some cases a substance's temperature will change when energy is added to the substance. In other cases, the substance's temperature will not change when energy is added.

The earth moves in a closed almost circular orbit around the sun. Since its path is a circular orbit, the Earth is also experiencing an acceleration all the time. But this force/acceleration being at right angles to the pathof the earth does not change magnitude of the velocity or the speed with which earth revolves around the sun. So, yes the earth does have an acceleration.

Is the Earth accelerating?

Use Kepler's second law to convince yourself that Earth must move faster in its orbit during the northern hemisphere winter, when it is closest to the Sun than during the summer, when it is farthest from the Sun.

Kepler's second law says that equal areas are swept out in equal times by a line drawn from the Sun to the Earth. For this to be so, the planet must move fastest when it is closest to the Sun. This, surprisingly, occurs during the winter in the northern hemisphere.

melting or freezing

Latent heat of fusion

Boiling or condensing

Latent heat of vaporization

c. two down quarks and one up quark

Neutron is composed of: a. three down quarks b. three up quarks c. two down quarks and one up quark d. two up quarks and one down quark

Area under the curve

On a Stefan-Boltzmann plot of intensity vs wavelength, how do we determine total radiation emitted?

D. specific heat

On a sunny day at the beach, the reason the sand gets so hot and the water stays relatively cool is attributed to the difference in which property between water and sand? A. mass density B. temperature. C. thermal conductivity D. specific heat

b. helium

One container is filled with argon gas and another with helium gas. Both containers are at the same temperature. Which atoms have the higher rms speed? a. argon b. helium c. they have the same speed d. not enough information to say

a. False b. True c. False d. False

Respond to each statement, true or false: a. No force of gravity acts on an astronaut in an orbiting space station b. At three Earth radii from the center of Earth, the acceleration of gravity is 1/9 its surface value c. If two identical planets, each with surface gravity g and volume V, coalesce into one planet with volume 2V, the surface gravity of the new planet is 2g d. One kilogram of gold would have greater value on Earth than on the moon

True

Speed of an object moving in the two-dimensions is a magnitude of the object's velocity vector. True False

c). Both take the same time. Because force equals the time rate of change of momentum, the two balls lose momentum at the same rate. If both balls initially have the same momentum, it takes the same amount of time to stop them.

Suppose a ping-pong ball and a bowling ball are rolling toward you. Both have the same momentum, and you exert the same force to stop each. How do the time intervals to stop them compare? a). It takes less time to stop the ping-pong ball. b). Can not be determined from the information given. c). Both take the same time. d). It takes more time to stop the ping-pong ball.

c. aluminum, gold, silver

Suppose you have one cubic meter of gold, two cubic meters of silver, and six cubic meters of aluminum. Rank them by mass, from smallest to largest.

Option b is easier. By exerting an upward force component on the sled, you reduce the normal force on the ground and so reduce the force of kinetic friction.

Suppose your friend is sitting on a sled and asks you to move her across a flat, horizontal field. You have a choice of: a. pushing her from behind by applying a force downward on her shoulders at 30 degrees below the horizontal b. attaching a rope to the front of the sled and pulling with a force at 30 degrees above the horizontal Which option would be easier and why?

a. electromagnetic force.

Tension force has its origin in which of these fundamental forces? a. electromagnetic force. b. gravitational force. c. nuclear force. d. weak nuclear force.

The moon can be considered a projectile that is falling around the earth, for, in fact, the moon does have a velocity that is tangential to its orbital motion. That motion is fast enough for it to fall around the earth, rather than into it.

The Moon does not fall to Earth because...

b. equal to

The density of lead is greater than iron, and both metals are denser than water. Is the buoyant force on a solid lead object: a. greater than b. equal to c. less than the buoyant force acting on a solid iron object of the same dimensions

In a force vs. displacement graph, the area under the line gives the work done by the force and the work done will be the change in the K so the largest area is the most K change

The following graphs, all drawn to the same scale, represent the net force F as a function of position x for an object that moves along a straight line. Which graph represents the force that will cause the greatest gain in the kinetic energy of the object from x = 0 to x = x1? [Explain why please]

C. change in momentum of a gas molecule due to collision with wall

The force on the walls of a vessel of a contained gas is due to: A. repulsive force between gas molecules B. slight loss in average speed of a gas molecule after collision with wall C. change in momentum of a gas molecule due to collision with wall D. elastic collisions between gas molecules E. inelastic collisions between gas molecules

In a force versus time curve, how would we determine impulse? What else can we say this is equal to?

The impulse imparted to the particle by the force is the area under the curve of the force versus time curve.This area is also equal to the change in momentum

The weight of the displaced water

The magnitude of the buoyance force equals what?

c. 20 and 4

The magnitude of two vectors A and B are 12 units and 8 units, respectively. What are the largest and smallest possible values for the magnitude of the resultant vector R = A + B?

a. smaller than P

The pressure at the bottom of a glass filled with water is P. The water is poured out and the glass is filled with ethyl alcohol (p = 806 kg/m^3). The pressure at the bottom of the glass is now: a. smaller than P b. equal to P c. larger than P d. indeterminate

C. greater than P.

The pressure at the bottom of a glass of fresh water is P. The water is poured out and is replaced with seawater. The new pressure at the bottom of the glass is A. smaller than P. B. equal to P. C. greater than P. D. indeterminate.

A pail of water can be whirled in a vertical circular path such that no water is spilled. Why does the water remain in the pail, even when the pail is upside down above your head?

The tendency of the water is to move in a straight line path tangent to the circular path followed by the container. As a result, at the top of the circular path, the water is forced against the bottom of the pail, and the normal force exerted on the water by the pail provides the radial force required to keep the water moving in its circular path.

B

The three graphs in figure 2.13 represent the position vs. time for objects moving along the x-axis. Which, if any, of these graphs is not physically possible?

b. 9.8 m/s2

The value of g to be substituted in the Equations [3.14 a-c] is a. 4.9 m/s2 b. 9.8 m/s2 c. 0 d. -9.8 m/s2

d. can have opposite signs.

The velocity and acceleration of an object a. must have opposite signs. b. must have the same sign. c. must both be zero simultaneously; one cannot be zero and the other nonzero. d. can have opposite signs.

you are re shelving books in a library. you lift a book from the floor to the top shelf. the kinetic energy of the book on the floor was zero and the kinetic energy of the book on the top shelf is zero, so there is no change in kinetic energy. yet you did some work in lifting the book. is the work kinetic energy theorem violated?

There is no violation. Choose the book as the system. You did work and the earth did work on the book. The average force you exerted just counterbalanced the weight of the book. The total work on the book is zero, and is equal to its overall change in kinetic energy, which is also zero.

C. The two weigh the same.

Two cups are filled to the same level with water. One of the two cups has plastic balls floating in it. If the density of the plastic balls is less than that of ice, which of the two cups weighs more? A. The cup without plastic balls. B. The cup with plastic balls. C. The two weigh the same.

Two objects in thermal equilibrium with each other are at the same temperature

Under what conditions can we say that two objects are in thermal equilibrium with each other?

b. A particle moves in the -x direction without reversing.

Under which of the following conditions is the magnitude of the average velocity of a particle moving in one dimension the same as the average speed over the time interval? a. A particle moves in the +x direction and then reverses the direction of its motion. b. A particle moves in the -x direction without reversing. c. There are no conditions for which this is true. d. A particle moves in the -x direction and then reverses the direction of its motion.

The volume of fluid that enters one end of the tube in a given time interval equals the volume of fluid leaving the tube in the same interval

Voiceover: Equation of continuity

Every part of the gas is at the same temperature Every part of the gas is at the same pressure

What can be said about temperature and pressure of an ideal gas at equilibrium?

PV^y = constant, where y = Cp/Cv y is called the adiabatic index of the gas

What can we say about the ideal gas law for an ideal gas undergoing an adiabatic process?

Adibiatic process

What do we call a process wherein heat is zero?

Isobaric

What do we call a process wherein pressure is constant?

Isothermic

What do we call a process wherein temperature is constant?

1. In general, liquids become more dense as they cool, because mass stays the same while volume decreases (P=m/v). This isn't true for water, though! At 4C, water starts to expand, and therefore becomes less dense 2. Water has the highest specific heat of any liquid

What do we mean when we say 'unusual behavior of water'?

Tells us how much energy is being emitted or absorbed by the object at a certain temperature

What does intensity on a Stefan-Boltzmann plot tell us?

3/2nRΔT 100% depends on Temperature

What does internal energy depend upon?

Characteristics of the substance, including: thermal conductivity, k width of object, delta x Difference in temperatures (in Kelvin, T-T)

What does rate of conduction depend upon?

ΔU = W

What is internal energy in an adiabatic process?

During a phase change, amount of heat is given by: Q = +- m*L, where L is the latent heat Choose positive sign if adding, negative sign if subtracting

What is latent heat? Why do we care?

Entropy must increase in all natural processes in isolated systems - entropy of some system can decrease, but with a corresponding net increase in entropy for some other system. When all systems are taken together, then, the entropy of the universe always increases. Ultimately, the entropy of the universe should reach a maximum. When it does, the Universe will be in a state of uniform temperature and density. All physical, chemical, and biological processes will cease, because a state of perfect disorder implies no available energy for doing work. This gloomy state of affairs is sometimes referred to as the ultimate "heat death" of the Universe.

What is meant by the 'heat death' of the universe?

The physical cause of the buoyant force is the pressure difference between the top and the bottom of the object (pressure is different because they're at different levels y)

What is the cause of the buoyant force?

ΔU = Q + W

What is the first law of thermodynamics?

b). zero.

When a disk rotates counterclockwise at a constant rate about a vertical axis through its center, the tangential acceleration of a point on the rim is... a). positive. b). zero. c). negative. d). impossible to determine without more information.

True

When an object moves with a constant acceleration, the instantaneous acceleration at any point in the time interval is equal to the value of the average acceleration over the entire time interval. True False

When pressure is constant

When can the equation W = -pΔV be applied?

a. the force of gravity you exert on the Earth

When you sit in a chair there is necessarily a reaction force to the gravitational force acting on your body. Which of the following best describes this reaction force? a. the force of gravity you exert on the Earth b. the force you exert downward on the seat of the chair c. none of these forces d. the normal force exerted by the chair onto you

b. The newton of gold on the moon

Which has a greater value, a newton of gold won on Earth or a newton of gold won on the moon? a. The newton of gold on Earth b. The newton of gold on the moon c. The value is the same, regardless

D. an increase in the pressure at constant volume

Which of the following could be associated with a temperature increase for a fixed amount of gas? A. a decrease in the volume at constant pressure B. a decrease in the pressure at constant volume C. a decrease in both the pressure and the volume D. an increase in the pressure at constant volume

A. One gram of steam at 100°C changing to water at 100°C.

Which of the following involves the greatest heat transfer? A. One gram of steam at 100°C changing to water at 100°C. B. One gram of ice at 0°C changing to water at 0°C. C. One gram of water cooling from 100°C to 0°C. D. One gram of ice heating from -100°C to 0°C.

b). the force of friction.

Which of the following is not a conservative force? a). the force exerted by a spring on a particle in one dimension. b). the force of friction. c). the force of gravity. d). the electrostatic force.

The feet of a standing person of mass m exert a force equal to mg on the floor, and the floor exerts an equal and opposite force upwards on the feet, which we call the normal force. During the extension phase of a vertical jump, the feet exert a force on the floor that is greater than mg, so the normal force is greater than mg. Using energy ideas, we know that work is performed on the jumper to give him or her kinetic energy. But the normal force can't perform any work here because the feet don't undergo any displacement. How is energy transferred to the jumper?

Work is actually performed by the thigh bone (the femur) on the hips as the torso moves upwards a distance h. The force on the torso is approximately the same as the normal force (since the legs are relatively light and are not moving much), and the work done by minus the work done by gravity is equal to the change in kinetic energy of the torso. At full extension the torso would continue upwards, leaving the legs behind on the ground (!), except that the torso now does work on the legs, increasing their speed (and decreasing the torso speed) so that both move upwards together.

in a race like the indianapolis​ 500, a driver circles the track counterclockwise and feels his head pulled to one shoulder. to relieve his neck muscles from having to hold his head erect, the driver fastens a strap to one wall of the car and the other to his helmet. the length of his strap is adjusted to keep his head vertical. what force produces the centripetal acceleration when there is no strap?

tension in the neck muscles

in a race like the indianapolis​ 500, a driver circles the track counterclockwise and feels his head pulled to one shoulder. to relieve his neck muscles from having to hold his head erect, the driver fastens a strap to one wall of the car and the other to his helmet. the length of his strap is adjusted to keep his head vertical. what happens to the force when there is a strap?

with tension in the strap, neck muscles are able to relax

If a car's wheels are replaced with wheels of greater diameter, will the reading of the speedometer change?

yes Explanation: The speedometer will be inaccurate. The speedometer measures the number of tire revolutions per second, so itsreadings will be too low.

Rate at which heat enters the room depends on the thickness of the walls (so heat will enter the room slowly)

Why is it nice to be in a basement with thick walls on a hot day?

2 > 1 = 4 > 3

You are using a wrench and trying to loosen a rusty nut (see figure). List in order of descending efficiency the arrangements shown in a figure.

The difference in the tension forces is the buoyant force

You have an object suspended by a string in air. Then, that same object is put into water. How do you calculate the difference in the tension forces?

discuss whether any work is being done by each of the following agents, and if so, whether the work is positive or negative: a) chicken scratching the ground b) person studying c) crane lifting a bucket of concrete d) gravity on the bucket in part c e) leg muscles of a person in the act of sitting down

a) positive b) no work c) positive d) negative e) negative

If someone told you that astronauts are weightless in Earth orbit because they are beyond the force of gravity, would you accept the statement?

no Explanation: The statement is wrong for two reasons. First, gravity is the centripetal force that keeps the astronauts and their spacecraft in orbit around the Earth, so the astronauts aren't beyond gravity's influence. Second, weight is the magnitude of the gravitational force, so astronauts inEarth orbit have weight, although it's lower than on Earth's surface. Because they are freely falling around the Earth along with their spacecraft environment, gravity doesn't press them against the cabin's walls or floor, giving rise to the feeling of weightlessness. The same feeling of weightlessness would occur in a freely falling elevator.

b. exactly 9.8 m/s2

A ball is thrown (not dropped) from the top of the tower and is in the free fall motion. Its downward acceleration is a. zero b. exactly 9.8 m/s2 c. larger than 9.8 m/s2 d. smaller than 9.8 m/s2

b

A train is traveling with a speed of 50 miles/h with respect to the ground in the positive x-direction. A baseball player standing at the rear of the train pitches a baseball with a speed of 50 miles/h relative to the train off the back end, in the direction opposite the motion of the train. You are standing on the ground, observing the baseball. Which of the curves below best describes the path followed by the baseball in the previous question as seen by you?

Δ Velocity: the area under an acceleration curve represents the change in velocity. In other words, the area under the acceleration graph for a certain time interval is equal to the change in velocity during that time interval

Given a graph, how would you identify Δ Velocity?

Radiation thermometer measures the intensity of the infrared radiation from the eardrum

How does a radiation thermometer work?

You apply a force to the balloon end, and increase the speed of the air. Since air speed increases, pressure is reduced. This creates a net force from the pressure below, inside the bottle, that prompts it to dispense fluid.

How does an old-fashioned perfume bottle work?

b. go down briefly before reaching a final reading

If you quickly plunge a room-temperature mercury thermometer into hot water, the mercury level will: a. go up briefly before reaching a final reading b. go down briefly before reaching a final reading c. not change

True! Specific heat of liquid water is highest, followed by steam, followed by ice

T/F: The same substance in different phases can have different specific heats Use water as an example to justify your claim

True

T/F: The spring potential energy of a stretched or compressed spring is always positive

False

T/F: The total momentum and the total energy of an isolated system is always conserved in a glancing collision of two objects.

b. A represents an isothermal process and B represents an adiabatics process.

The relation PV = nRT holds for all ideal gases. The additional relation PVγ holds for an adiabatic process. The figure below shows two curves: one represents an adiabatic process and one represents an isothermal process. Each starts at the same pressure and volume. Which statement is correct? a. A represents an adiabatic process and B represents isothermal process. b. A represents an isothermal process and B represents an adiabatics process. c. Both curves represent an adiabatic process d. Both curves represent an isothermal process.

a. work is done by a gas at constant pressure.

The specific heat of an ideal gas at constant pressure is greater than the specific heat of an ideal gas at constant volume because a. work is done by a gas at constant pressure. b. work is done by a gas at constant volume. c. no work is done by a gas at constant pressure. d. the temperature remains constant for a gas at constant pressure. e. the temperature remains constant for a gas at constant volume.

a). perfectly inelastic collisions

The statement "The momentum is conserved, the kinetic energy is not conserved and the final velocities of the two objects are the same" describes: a). perfectly inelastic collisions b). inelastic collisions c). all of the above d). elastic collisions

Average KE is given entirely by T KEaverage = N3/2KbT = 3/2nRT

What's the relationship between KE and T?

Thermal equilibrium exists when two objects in thermal contact with each other cease to exchange energy

When does thermal equilibrium exist?

c. (ii) and (iii)

Which of the following quantities, if any, remain constant as a projectile moves through its parabolic trajectory? (i) speed (ii) acceleration (iii) the horizontal component of velocity (iv) the vertical component of velocity a. (i) only b. (ii) and (iv) c. (ii) and (iii) d. all of them

B. 0.100 kg of water at 22 oC

Which of the following substances would be the most effective in cooling 0.300 kg of water at 98 °C? A. 0.100 kg of lead at 22 oC B. 0.100 kg of water at 22 oC C. 0.100 kg of glass at 22 oC D. 0.100 kg of iron at 22 oC

a. the vibration of a Cs-133 atom

Which of the following would serve as the best time standard? a. the vibration of a Cs-133 atom b. the rotation of Earth upon its axis c. a grandfather clock d. the buzzing of a mosquito

Vector B

Which vector has an angle with respect to the positive x-axis that is in the range of the inverse tangent function?

Instantaneous acceleration

the instantaneous acceleration of an object at a given time equals the slope of the tangent line to the velocity vs. time graph at that time. In the special case where the velocity vs. time graph of an object's motion is a straight line, the instantaneous acceleration of the object at any point is equal to its average acceleration

A batter bunts a pitched baseball, blocking the ball without swinging. (a) Can the baseball deliver more kinetic to the bat and batter than the ball carries initially? (b) Can the baseball deliver more momentum to the bat and batter than the ball carries initially? Explain.

(a) No. It cannot carry more kinetic energy than it possesses. That would violate the law of energy conservation. (b) Yes. By bouncing from the object it strikes, it can deliver more momentum in a collision than it possess in its flight.

If two objects collide and one is initially at rest, (a) is it possible for both to be at rest after the collision? (b) Is it possible for only one to be at rest after the collision? Explain.

(a) No. One of the objects was in motion before collision, so the system consisting of the two particles had a nonzero momentum before impact. Since momentum is always conserved in collisions, the system must have nonzero momentum after impact, meaning that at least on of the particles must be in motion. (b) Yes. It is possible for one of the particles to be at rest after collision, provided the other particle leaves the collision with a momentum equal to the total momentum of the two-particle system before impact.

In golf, novice players are often advised to be sure to "follow through" with their swing. (a) Why does this make the ball travel a longer distance? (b) If a shot is taken near the green, very little follow-through is required. Why?

(a) The follow-through keep the club in contact with the ball as long as possible, maximizing the impulse. Thus, the ball accrues a larger change in momentum than without the follow-through, and it leaves the club with a higher velocity and travels farther. (b) With a short shot to the green, the primary factor is control, not distance. Hence, there is little of no follow-through, allowing the golfer to have a better feel for how hard he/she is striking the ball.

b). The ball undergoes the same acceleration as Earth c). The magnitude of the force the Earth exerts on the ball is greater than the magnitude of the force the ball exerts on the Earth

A ball is falling toward the ground. Which of the following statements are false? a). The force that the ball exerts on Earth is equal in magnitude to the force that Earth exerts on the ball b). The ball undergoes the same acceleration as Earth c). The magnitude of the force the Earth exerts on the ball is greater than the magnitude of the force the ball exerts on the Earth

a. exactly the free-fall acceleration g.

A ball is thrown downward from the top of a tower. After being released, its downward acceleration will be a. exactly the free-fall acceleration g. b. answer depends on a height of a tower c. greater than the free-fall acceleration g. d. smaller than the free-fall acceleration g.

The maximum kinetic energy occurs at the point of release and the maximum gravitational potential energy occurs at the top of the ball's trajectory

A ball is thrown straight up in the air. At what position is its kinetic energy a maximum? At what position is the gravitational potential energy of the ball a maximum? Consider only the trip up.

c. at the top of the trajectory

A baseball is thrown by the center fielder (from shoulder level) to home plate where it is caught (on the fly at shoulder level) by the catcher. At what point does the magnitude of the vertical component of velocity have its minimum value? (air resistance is negligible) a. magnitude of vertical component of velocity is constant b. just before arriving at the catcher's mitt c. at the top of the trajectory d. just after leaving the center fielder's hand

b. B

A battleship simultaneously fires two shells at enemy ships at exactly same initial speeds but at different angles. If the shells follow the parabolic trajectories which ship gets hit first? (neglect air resistance) a. both at the same time . b. B c. A d. need more information

d). 4

A block initially at rest is allowed to slide down a frictionless ramp and attains speed V at the bottom. To achieve a speed 2V at the bottom, how many times as high must a new ramp be? a). 1 b). 2 c). 3 d). 4 e). 5 f). 6

b. less than the time for the trip down.

A block is launched up an incline plane. After going up the plane, it slides back down to its starting position. The coefficient of friction between the block and the plane is 0.3. The time for the trip up the plane: a. is more than the time for the trip down. b. less than the time for the trip down. c. cannot be found without knowing the angle of inclination. d. is the same as the time for the trip down.

b). The combined net work done by all three forces is zero.

A block slides at constant speed down a ramp while acted on by gravity, normal force and kinetic friction. Which of the following statements is correct? a). Each force does negative work on the block as it slides. b). The combined net work done by all three forces is zero. c). Each force does a positive work on the block as it slides. d). Each force does zero work on the block as it slides.

A. an increase in pressure.

A blood platelets drifts along with the flow of blood through an artery that is partially blocked by deposits. As the platelet moves from the narrow region to the wider region, it experiences A. an increase in pressure. B. no change in pressure. C. a decrease in pressure. D zero pressure.

c). It's smaller on the tilted surface (the decrease in mechanical energy of they system is fkdeltax. this has a smaller value on the tilted surface for two reasons. (1) the force of kinetic friction fk is smaller b/c the normal force, and (2) the displacement deltax is smaller b/c a component of the gravitational force is pulling on the book in the direction opposite to its velocity.)

A book of mass m is projected with a speed v across a horizontal surface. The book slides until it stops due to the friction force between the book and the surface. The surface is now tilted 30 degrees, and the book is projected up the surface with the same initial speed v. When the book has come to rest, how does the decrease in mechanical energy of the book-Earth system compare with that when the book slid over the horizontal surface? a). It's the same b). It's larger on the tiled surface c). It's smaller on the tilted surface d). More information is needed

a. mg sin θ.

A box of mass m is placed on an incline with angle of inclination θ. The box does not slide. The magnitude of the frictional force in this case is: a. mg sin θ. b. mg cos θ. c. μsmg sin θ. d. μsmg cos θ.

C If the box is about to tip over, its weight will be resting mainly on its leftmost corner. Assume that this is the starting point. Make that the pivot, then the only torque comes from gravity on the box. In cases A, B, and D, the gravitation torque makes it rotate clockwise, which increases its stability. In the case of C, the torque is counterclockwise, which makes it tip over

A box, with its center of mass of -center as indicated by the dot in the figure, is placed on an incline plane. In which of the four orientations shown, does the box tip over?

a). The tension increases to four times its original value. everything stays the same except the speed (v) which doubles. When v doubles it quadruples bc (2)^2 = 4

A boy is whirling a stone at the end of a string around his head. The string makes one complete revolution every second, and the tension in the string is T. The boy increases the speed of the stone, keeping the radius of the circle unchanged, so that the string makes two complete revolutions per second. What happens to the tension in the sting? a). The tension increases to four times its original value. b). The tension increases to twice its original value. c). The tension is unchanged. d). The tension is reduced to one half of its original value. e). The tension is reduced to one fourth of its original value.

c). moves toward the shore

A boy standing at one end of a floating raft that is stationary relative to the shore walks to the opposite end of the raft, away from the shore. As a consequence, the raft... a). remains stationary b). moves away from the shore c). moves toward the shore

c). Both vehicles experience the same magnitude change in momentum.

A car and a large truck make a head-on collision and stick together. Prior to the collision, the truck's velocity was twice that of the car. Which vehicle experiences the larger change of its momentum? a). the car. b). the truck. c). Both vehicles experience the same magnitude change in momentum. d). Impossible to determine without knowing the speeds.

c). the change in the magnitude of momentum is the same for both

A car and a large truck traveling at the same speed collide head-on and stick together. Which vehicle undergoes the larger change in the magnitude of its momentum? a). the car b). the truck c). the change in the magnitude of momentum is the same for both d). impossible to determine without more information

b. 10 m/s

A car leaves a garage and travels north for 100 m, then it reverses its direction of travel along the same road and comes back to the garage. The whole trip took 20 seconds. What is the average speed of the car? a. 0 m/s b. 10 m/s c. -5 m/s d. 5 m/s e. -10 m/s

c. 0

A car leaves a garage and travels north for 100 m, then it reverses its direction of travel along the same road and comes back to the garage. The whole trip took 20 seconds. What is the average velocity of the car? a. 5 m/s b. -10 m/s c. 0 d. -5 m/s e. 10 m/s

b). Yes Acceleration is a change in the speed and/or direction of an object. Thus, because its direction has changed, the car has accelerated and a force must have been exerted on it.

A car rounds a curve while maintaining a constant speed. Is there a net force on the car as it rounds the curve? a). No-its speed is constant. b). Yes. c). It depends on the sharpness of the curve. d). It depends on the speed of the car.

a). Yes; both can be larger. The cart's momentum has magnitude mv and its kinetic energy is ½mv². If the cart's speed increases, its momentum and kinetic energy will increase. It is not possible for the kinetic energy but not the magnitude of momentum to increase, or vice versa. Thus, answers (2) and (3) are impossible. But is it possible for the speed to increase, thus causing momentum and kinetic energy to increase? Yes! For example, the cart could be rammed from behind by something moving faster. Not all collisions are head-on! Or, it could collide head-on with an object having a much larger momentum. Even if it sticks to the object, its final speed can be larger than its initial speed (though in the opposite direction). For instance, if the cart collides head-on with a cart of mass 3m and speed v moving to the left, and energy is conserved, then the 3m cart is at rest after the collision, and the m cart is moving to the left with speed 2v. You may be thinking that momentum is always conserved in a collision, and kinetic energy is either conserved or lost depending on whether the collision is elastic or inelastic. This is true, but for the entire system, not for each individual object involved. Key Points: •If an object's kinetic energy increases, the magnitude of its momentum must also increase. •Energy and momentum can be transferred between objects during a collision, and sometimes one object ends up with more than it had to start. •When trying to figure out whether some general statement about physics is possible, think of extreme examples. For Instructors Only Most collision problems students encounter in physics are head-on and in many cases cause both objects to slow down, so students might erroneously generalize. This question helps to remedy that. Ask your students how many considered a rear-end (or even side-on) collision. Another common mistake is for students to automatically apply "momentum is conserved" or "energy is conserved or lost" ideas without thinking through what system or bodies these apply to. Some confusion is possible about whether "larger", for momentum, depends on the sign as well as the magnitude. We intend this question to be about the magnitude only, but as with all ambiguities, the best result is to have the confusion articulated and discuss how the choice of interpretation would affect students' answers.

A cart of mass m is moving with speed v. Is it possible for the cart's kinetic energy or the magnitude of its momentum to be larger after it collides with something? a). Yes; both can be larger. b). Yes; the momentum can be larger. c). Yes; the kinetic energy can be larger. d). No; it is impossible.

c). car (Newton's Second Law, ↓m, ↑ a)

A compact car and a large truck collide head on and stick together. Which vehicle undergoes the larger acceleration during the collision? a). Both experience the same acceleration. b). truck c). car d). Can't tell without knowing the final velocity of combined mass.

b. to the east

A crate is sitting in the center of a flatbed truck. As the truck accelerates to the east, the crate moves with it, not sliding on the bed of the truck. In what direction is the friction force exerted by the bed of the truck on the crate? a. to the west b. to the east c. there is no friction force, because the crate isn't sliding

a). half the ladybug's.

A ladybug sits at the outer edge of a merry-go-round, and a gentleman bug sits halfway between her and axis of rotation (see a figure). The merry-go-round makes a complete revolution once each second. The gentleman bug's tangential speed is... a). half the ladybug's. b). the same as ladybug's. c). twice the ladybug's. d). impossible to determine.

e). +z direction

A ladybug sits at the outer edge of a merry-go-round, and a gentleman bug sits halfway between her and axis of rotation (see figure below). The merry-go-round makes a complete revolution once each second. The vector expressing ladybug's angular velocity is in the... a). +x direction b). -x direction c). +y direction d). -y direction e). +z direction f). -z direction

d). the rubber ball Because momentum is conserved in these interactions, more momentum is transferred to the bowling pin from the rubber ball than from the putty ball. Hence, the rubber ball is more likely to knock the pin over.

A person attempts to knock down a large wooden bowling pin by throwing a ball at it. The person has two balls of equal size and mass, one made of rubber and the other of putty. The rubber ball bounces back, while the ball of putty sticks to the pin. Which ball is more likely to topple the bowling pin? a). need more information. b). makes no difference. c). the ball of putty d). the rubber ball

2

A person initially at point P in the illustration below stays there a moment and then moves along the axis to Q and stays there a moment. She then runs quickly to R, stays there a moment, and then strolls slowly back to P. Which of the position vs. time graphs below correctly represents this motion?

c. neither-they both hit at the same speed

A person standing at the edge of a cliff throws one ball straight up and another ball straight down at the same initial speed. Neglecting air resistance, the ball to hit the ground below the cliff with the greater speed is the one initially thrown a. upward b. the answer depends on a size of the balls c. neither-they both hit at the same speed d. downward

c. Both experience the same force.

A race car moving quickly around a track collides with a mosquito, which splatters on the car's windshield. Which object experiences a greater magnitude impact force? a. One cannot tell, you need to know the speeds of the mosquito and the race car. b. the race car. c. Both experience the same force. d. the mosquito

e). the tangential acceleration is zero at both points

A racetrack is constructed such that two arcs of radius 80m at A and 40m at B are joined by two stretches of straight track. In a particular trial run, a driver travels at a constant speed of 50m/s for one complete lap. 1. The ratio of the tangential acceleration at A to that at B is... a). 1/2 b). 1/4 c). 2 d). 4 e). the tangential acceleration is zero at both points

e). The final kinetic energy is one half of the initial kinetic energy.

A sled of mass m is coasting at a constant velocity on the ice covered surface of a lake. Three birds, with a combined mass 0.5m, gently land at the same time on the sled. The sled and birds continue sliding along the original direction of motion. How does the kinetic energy of the sled and birds compare with the initial kinetic energy of the sled before the birds landed? a). The final kinetic energy is equal to the initial kinetic energy. b). The final kinetic energy is one quarter of the initial kinetic energy. c). The final kinetic energy is one third of the initial kinetic energy. d). The final kinetic energy is one ninth of the initial kinetic energy. e). The final kinetic energy is one half of the initial kinetic energy.

c. neither, the force is the same on both d. the car

A small sports car collides head on with a massive truck. The greater impact force (in magnitude) acts on: a. the car b. the truck c. neither, the force is the same on both Which vehicle undergoes the greater magnitude acceleration? d. the car e. the truck. f. the accelerations are the same on both

b). The force on B is half the force on A. F = mv^2/r. For car B traveling on the outside, the radius is 2r: FB = mv^2/ (2r) . For car A traveling on the inside, the radius is r: FA = mv^2/ r. Here m and v are constant. Therefore the force on B is 1/2 that of the force on A.

A split highway has a number of lanes for traffic. For traffic going in one direction, the radius for the inside of the curve is half the radius for the outside. One car, car A, travels on the inside while another car of equal mass, car B, travels at equal speed on the outside of the curve. Which statement about resultant forces on the cars is correct? a). The force on A is half the force on B. b). The force on B is half the force on A. c). The force on A is four times the force on B. d). The force on B is four times the force on A. e). There is no net resultant force on either as long as they stay on the road while turning.

b. 0 miles/h

A train is traveling with a speed of 50 miles/h with respect to the ground in the positive x-direction. A baseball player standing at the rear of the train pitches a baseball with a speed of 50 miles/h relative to the train off the back end, in the direction opposite the motion of the train. You are standing on the ground, observing the baseball. What is the velocity of the baseball at the moment of the throw that you observe? a. 100 miles/h in the positive x-direction. b. 0 miles/h c. 100 miles/h in the negative x-direction. d. 50 miles/h in the negative x-direction.

a). The boat will move off on a line tangent to the circle because there is no force on it.

An iceboat is traveling in a circle on the ice. Halfway around the circle the sail and the steering mechanism fall off the boat. Which statement is correct? a). The boat will move off on a line tangent to the circle because there is no force on it. b). The boat will continue traveling in the circle because there is no friction. c). The boat will continue to travel in the circle because its velocity exerts a force on it d). The boat will move off tangent to the circle because there is a force on it perpendicular to the boat directed to the outside of the circle. e). The boat will move off to the outside perpendicular to the tangent line since a force directed to the outside of the circle always acts on the boat.

c). Both its velocity and acceleration are changing

An object moves in a circular path with constant speed v. Which of the following statements is true concerning the object? a). Its velocity is constant, but its acceleration is changing b). Its acceleration is constant, but its velocity is changing c). Both its velocity and acceleration are changing d). Its velocity and acceleration remain constant

a. A single force acts on the object.

An object moves with a constant velocity. Which of the following cannot be true for the object? a. A single force acts on the object. b. Two forces act on the object. c. Three forces act on the object. d. No forces act on the object.

a). 0

An object of mass m moves to the right with a speed v. It collides head-on with an object of mass 3m moving with speed v/3 in the opposite direction. If the two objects stick together, what is the speed of the combined object, of mass 4m, after the collision? a). 0 b). v/2 c). v d). 2v

b. if the process is adiabatic

Assume that a closed system undergoes a reversible process that takes it from state A to a different state B. In which of these cases will the entropy of the system remain constant? a. if the process is isothermal b. if the process is adiabatic c. if the process is isovolumetric d. The system's entropy will remain constant for all of these cases.

c). The clown is trying to keep the center of mass of the ladder directly above his head so that the torque due to the gravitational force is zero.

At the circus, a clown balances a step ladder on his forehead. A few people in the audience notice that he is continually moving to keep the ladder from falling off his forehead. Why is this movement necessary? a). By rocking the ladder on his forehead, the ladder will be more stable than if it were stationary. This is similar to riding a bicycle. You can easily balance a bicycle when it's rolling, but not when it's stationary. b). This movement is not necessary. The clown is trying to make this look harder than it really is for entertainment value. The ladder will easily balance in the clown's forehead. c). The clown is trying to keep the center of mass of the ladder directly above his head so that the torque due to the gravitational force is zero. d). The clown is trying to apply a torque to the ladder in the direction opposite to other torques on the ladder.

b. greater than it is for the arm

Blood pressure is normally measured with the cuff of the sphygmomanometer around the arm. Suppose the blood pressure is measured with the cuff around the calf of the leg of a standing person. Would the reading of the blood pressure be: a. the same here as it is for the arm b. greater than it is for the arm c. less than it is for the arm

A pendulum consists of a small object called a bob hanging from a light cord of fixed length, with the top end of the cord fixed, as represented in the figure. The bob moves without friction, swinging equally high on both sides. It moves from its turning point A through point B and reaches its maximum speed at point C. (a) At what point does the bob have nonzero radial acceleration and zero tangential acceleration? What is the direction of its total acceleration at this point? (b) At what point does the bob have nonzero tangential acceleration and zero radial acceleration? What is the direction of its total acceleration at this point? (c) At what point does the bob have both nonzero tangential and radial acceleration?What is the direction of its total acceleration at this point?

C, up Explanation: No tangential acceleration, there is no net force acting on it, component of mg along tangential direction is zero and just by looking at it you can clearly see the direction of total acceleration is upwards A, to the right downward and perpendicular to the cord Explanation: Component of mg along the rope will balance the tension but component of mg perpendicular to rope will provide acceleration so circular motion stops at that position B, to the right and upward Explanation: both tension and the component of mg perpendicular to rope is providing net force and hence acceleration

It has been suggested that rotating cylinders about 10 miles long and 5 miles in diameter be placed in space for colonies. The purpose of their rotation is to simulate gravity for the inhabitants. Explain the concept behind this proposal.

Consider an individual standing against the inside wall of the cylinder with her head pointed toward the axis of the cylinder. As the cylinder rotates, the person tends to move in a straight line path tangent to the circular path followed by the cylinder wall. As a result, the person is forced against the wall, and the normal force exerted on her provides the radial force required to keep her moving in a circular path. If the rotational speed is adjusted such that this normal force is equaling magnitude to her weight on Earth, she would not be able to distinguish between the artificial gravity of the colony and ordinary gravity.

a. all 3

Consider the following controls in an automobile: gas pedal, brake, steering wheel. The controls in this list that cause an acceleration of the car are: a. all 3 b. the gas pedal and the brake c. only the brake d. only the gas pedal

b. hits the criminal regardless of the value of v0

Consider the situation depicted in the figure below. A gun is accurately aimed at the dangerous criminal hanging from the gutter of the building. The target is well within the gun's range, but the instant the gun is fired and the bullet moves with speed v0, the criminal lets go and drops to the ground. What happens? (neglect air resistance) The bullet... a. can not be answered with information given. b. hits the criminal regardless of the value of v0 c. hits the criminal only if v0 is large enough. d. misses the criminal.

C only Can't be A because the position where force is applied matters!

Consider the three situations shown in the figure. Three forces act on the triangular object in different ways. Two of the forces have magnitude F and one of the forces has a magnitude 2F. In which case(s), if any, will the object be in equilibrium? A only B only A and B A and C C only

C. equal to the reading

Consider the two situations shown in the figure on page 99 of your book, in which there is no acceleration. In both cases the men pull with a force of magnitude F. Is the reading on the scale in part i of the figure: a. greater than b. less than c. equal to the reading in part ii?

e. It is equal to the momentum of the heavy cart. Momentum is equal to force times time. Because the forces on the carts are equal, as are the times over which the forces act, the final momenta of the two carts are equal. Momentum = mass * velocity-We don't know velocity Momentum also = Force * timeForces are same for both, time is same fro bothMomentums are equal

Consider two carts, of masses m and 2m, at rest on a frictionless track. If you push first cart for 3s and then the other for same length of time, exerting equal force on each, how does the momentum of the light cart compare to the momentum of the heavy cart? a). It is one-half of the momentum of the heavy cart. b). It is four times larger. c). It is two time larger. d). It is one-quarter of the momentum of the heavy cart. e). It is equal to the momentum of the heavy cart.

c. less than the total weight

For the woman being pulled forward on the toboggan in the figure, is the magnitude of the normal force exerted by the ground on the toboggan: a. equal to the total weight of the woman plus the toboggan b. greater than the total weight c. less than the total weight d. possibly greater than or less than, depending on the size of the weight relative to the tension in the rope

C. radiation

How does the heat energy from the Sun reach us through the vacuum of space? A. conduction B. convection C. radiation D. none of the above.

d. 1000 J

If a car engine has a thermal efficiency of 50% and it does 500 J of work in one cycle, how much energy input does it require each cycle? a. 250 J b. 500 J c. 750 J d. 1000 J

d. westward

If a car is traveling eastward and slowing down, what is the direction of the acceleration on the car that causes it to slow down? a. eastward b. No acceleration is required to slow the car. c. None of these choices is correct. d. westward

c). the collisions are all nearly elastic.

If ball 1 in the arrangement shown here is pulled back and then let go, ball 5 bounces forward. If balls 1 an 2 are pulled back and released, balls 4 and 5 bounce forward, and so on. The number of balls bouncing on each side is equal because: a). neither of the above. b). of conservation of energy only. c). the collisions are all nearly elastic. d). of conservation of momentum only.

False

If the x- and the y-component of a vector are both negative, an angle that this vector makes with positive x-axis is larger than 90o but smaller than 180o. True False

c. gasoline

If you are asked to make a very sensitive glass thermometer, which of the following working fluids would you choose? a. mercury b. alcohol c. gasoline d. glycerin

b. upward

If you press a book flat against a vertical wall with your hand, in what direction is the friction force exerted by the wall on the book? a. into the wall b. upward c. downward d. out from the wall

c). c, a, d, b

In Figure 5.5 (a) - (d), a block moves to the right in the positive x-direction through the displacement Δx(vector) while under the influence of a force with the same magnitude F(vector). Which of the following is the correct order of the amount of work done by the force F(vector), from most positive to most negative? a). d, c, a, b b). c, a, b, d c). c, a, d, b

d. there is no work done on or by the system.

In an isovolumetric process, a. there is never any transfer of energy by heat between the system and its surroundings. b. the pressure remains constant. c. the temperature remains constant. d. there is no work done on or by the system.

LESS! Because y (gamma) is always >1, because c at constant P has to be greater than at constant V, because gas is doing the work so more heat must be added. So, slope will be steeper, and the area underneath the curve will be less

Is the absolute value of work in adiabatic process greater or less than the absolute value of work in an isothermal process? Why?

A sharpshooter fires a rifle while standing with the butt of the gun against his shoulder. If the forward momentum of a bullet is the same as the backward momentum of the gun, why isn't it as dangerous to be hit by the gun as by the bullet?

It is the product mv that is the same for both the bullet and the gun. The bullet has a larger velocity and a small mass, while the gun had a small velocity and a large mass. Furthermore, the bullet carries much more KE than the gun.

Does a larger net force exerted on an object always produce a larger change in the momentum of the object, compared to a smaller net force? Explain.

No. Impulse (Fdeltatime) depends on the force and the time interval during which it is applied.

Does a larger net force always produce a larger change in kinetic energy than a smaller net force? Explain.

No. The change in kinetic energy of an object is equal to the net work done on it. This net work is the product of the net force acting on the object and the displacement in the direction of the force. Thus, a small magnitude force acting through a large distance may do more work (and hence produce a greater change in kinetic energy) than a large force acting through a small distance.

Relate net work done on an object, center of mass, and a person jumping into the air with arms outstretched

Note: An alternative way to think about problems that involve internal motions of an object is to note that the net work done on an object is equal to the net force times the displacement of the center of mass. Using this idea, the effect of throwing the arms upwards during the extension phase is accounted for by noting that the position of the center of mass is higher on the body with the arms extended, so that total displacement of the center of mass is greater.

d). 8 years

Suppose an asteroid has a semimajor axis of 4AU. How long does it take the asteroid to go around the Sun? a). 2 years b). 4 years c). 6 years d). 8 years

b). -1 rad, 1 rad

Suppose the change in angular position for each of the pairs of values below occurred in 1s. Which choice represents the lowest average angular speed? a). 3 rad, 6 rad b). -1 rad, 1 rad c). 1 rad, 5 rad

c. throw the ball straight up in the air and maintain the same speed

Suppose you are carrying a ball and running at constant speed, and wish to throw the ball and catch it as it comes back down. Should you: a. throw the ball at an angle of about 45 degrees above the horizontal and maintain the same speed b. throw the ball straight up in the air and slow down to catch it c. throw the ball straight up in the air and maintain the same speed

The number 7 is the most probable. The numbers 2 and 12 are the least probable.

Suppose you are throwing two dice in a friendly game of craps. For any given throw, the two numbers that are faceup can have a sum of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12. Which outcome is most probable? Which is least probable?

a. water, glass, iron b. iron, glass, water

Suppose you have 1 kg each of iron, glass, and water, and all three samples are at 10 degrees C. a. Rank the samples from lowest to highest temperature after 100 J of energy are added to each by heat b. Rank them from least to greatest amount of energy transferred by heat if enough energy is transferred so that each increases in temperature by 20 degrees C

False

T/F: The work done by a force during a displacement is always a positive scalar quantity.

True

T/F: When no external force acts on a system, the total momentum of the system is conserved.

c). The centripetal force is the net force acting on an orbiting object that maintains it in uniform circular motion.

The centripetal force is best explained by which of the following statements? a). The centripetal force is the force on an object that is directed radially outward from the center of its orbit. b). The centripetal force is the force on an orbiting object that is directed along a line that is tangent to the circle. c). The centripetal force is the net force acting on an orbiting object that maintains it in uniform circular motion. d). The centripetal force is a fundamental force of nature.

a. blue graph b. red graph c. green graph

The figure is a diagram of a multiflash image of an air puck moving to the right on a horizontal surface. The images sketched are separated by equal time intervals, and the first and last images show the puck at rest. a. In figure B, which color graph best shows the puck's position as a function of time? b. In figure c, which color graph best shows the puck's velocity as a function of time? c. In figure d, which color graph best shows the puck's acceleration as a function of time?

An object executes circular motion with constant speed whenever a net force of constant magnitude acts perpendicular to the velocity. What happens to the speed if the force is not perpendicular to the velocity? Explain.

The speed changes Explanation: The tangential force component causes tangential acceleration

Only 3 1 and 2 will never be in static equilibrium because the edges create non-zero net torque. RECALL - the force doesn't need to be applied in the opposite direction!

Three identical uniform rods are each acted on by two or more forces, all perpendicular to the rods. Which of the rods could be in static equilibrium if an additional force is applied at the center of mass of the rod? All three Only 1 Only 2 Only 3 Only 1 and 2

at night, you are farther away from the sun than during the day. what's more, the force exerted by the sun on you is downward into the earth at night and upward into the sky during the day. if you have a sensitive enough bathroom scale, would you appear to weight more at night than during the day? explain

To a good first approximation, your bathroom scale reading is unaffected because you, the Earth, and the scale are all in free fall in the Sun's gravitational field, in orbit around the Sun. To a precise second approximation, you weigh slightly less at noon and at midnight than you do at sunrise or sunset. The Sun's gravitational field is a little weaker at the center of the Earth than at the surface sub-solar point, and a little weaker still on the far side of the planet. When the Sun is high in your sky, its gravity pulls up on you a little more strongly than on the Earth as a whole. At midnight the Sun pulls down on you a little less strongly than it does on the Earth below you. So you can have another doughnut with lunch, and your bedsprings will still last a little longer.

b). p1 < p2

Two masses m1 and m2, with m1 < m2, have equal kinetic energy. How do the magnitudes of their momenta compare? a). not enough information is given b). p1 < p2 c). p1 = p2 d). p1 > p2

c. from the object at higher temperature to the object at lower temperature

Two objects with different sizes, masses, and temperatures are placed in thermal contact. Choose the best answer: Energy travels... a. from the larger object to the smaller object b. from the object with more mass to the object with less mass c. from the object at higher temperature to the object at lower temperature

c). The force will be one-sixteenth as great.

Two objects with masses m and M are separated by a distance d. If the distance between the objects is increased to 4d, how does the gravitational force between them change? a). The force will be one-half as great. b). The force will be one-forth as great. c). The force will be one-sixteenth as great. d). The force will be four times as great. e). The force will be sixteen times as great.

b. TA > TB

Two objects, A and B, are placed in thermal contact. The entropy of object A decreases. What can be said about the relationship between the temperatures of the two objects? a. TA < TB b. TA > TB c. TA = TB d. not enough information to say

b). remembering that momentum is a vector quantity that is conserved in each direction.

Two pucks on an air hockey table collide elastically. Complete the following statement: when such a collision occurs in two dimensions, the before and after velocities are best determined by: a). using the fact that momentum is conserved and that the initial speeds of the objects must equal the final speeds of the objects. b). remembering that momentum is a vector quantity that is conserved in each direction. c). making use of the work-energy theorem d). applying Newton's second law of motion and setting the net force equal to zero newtons.

b. when the rods are in parallel

Two rods of the same length and diameter are made from different materials. The rods are to connect two regions of different temperature so that energy will transfer through the rods by heat. They can be connected in series or in parallel. In which case is the energy transfer by heat larger? a. when the rods are connected in series b. when the rods are in parallel c. the rate is the same in both cases

b). sq. root of 1/2

Two satellites A and B of the same mass are going around Earth in concentric orbits. The distance satellite B from Earth's center is twice that of satellite A. What is the ratio of the tangential speed of B to that of A? a). 1/2 b). sq. root of 1/2 c). 1 d). sq. root of 2 e). 2

c. they expand by the same amount

Two spheres are made of the same metal and have the same radius, but one is hollow and the other is solid. The spheres are taken through the same temperature increase. Which sphere expands more? a. solid sphere b. hollow sphere c. they expand by the same amount d. not enough information to say

d. If two vectors have the same magnitude and the opposite direction.

Two vectors are to be added to each other. Under what conditions is the resultant vector equal to zero? a. If two vectors have the same magnitude and are perpendicular to each other. b. Adding two vectors can never result in the zero vector. c. If two vectors have the same magnitude and the same direction. d. If two vectors have the same magnitude and the opposite direction.

A conservative force is a force that does zero work done in a closed path. If only these forces act then the mechanical energy of the system remains conserved. Examples of conservative force: Gravitational force, spring force etc. On the other hand, non-conservative forces are those forces which cause loss of mechanical energy from the system. In the above case friction is the non-conservative force. But as we know energy can neither be created nor destroyed hence these forces convert mechanical energy into heat, sound, light etc.

What is a conservative force? What is a nonconservative force?

A cyclic process is one in which the process originates and ends at the same state The net work done per cycle by the gas (i.e. on the environment) is equal to the area enclosed by the path representing the process on a PV diagram

What is a cyclic process? How do we find net work?

A heat engine is a device that absorbs heat and converts a fraction of that energy into work A heat engine carries some working substance (like water) through a cyclical process A heat engine operates between two thermal reservoirs (hot and cold)

What is a heat engine?

Heat is energy exchanged between objects (note - heat itself is not energy. heat is exchange of energy)

What is heat?

Cv = 3/2R ΔU = nCvΔT

What is the expression for molar specific heat at constant volume for a monatomic ideal gas? How can we express change in internal energy here?

PV = nRT where n can be equal to m/M, but m MUST be in kg (so adjust accordingly) p is in Pa V is in m^3 R = 8.31 J/mol*K T is in Kelvin

What is the ideal gas law (physics version) including units?

0C

What is the temperature if water and ice are both present?

100C

What is the temperature if water and steam are both present?

At or around 4C, because this is the last temperature that the water would sink at (otherwise, it expands, and is less dense)

What is the temperature of water near the bottom of a lake?

The point at which water exists in all 3 phases. 273.16K, 0.01C

What is the triple point of water?

In order for a phase change to occur, energy must be added or taken away. This is because bonds must be loosened or formed. Important - no temperature change!

What needs to happen for a phase to change? Why?

a, c, and d

Which of the following statements are true? a. An object can move even when no force acts on it b. If an object isn't moving, no external forces act on it c. If a single force acts on an object, the object accelerates d. If an object accelerates, a force is acting on it e. If an object isn't accelerating, no external force is acting on it f. If the net force acting on an object is in the positive x-direction, the object moves only in the positive x-direction

b. If an equation is dimensionally correct it may be true and if it is not dimensionally correct then it cannot be true.

Which of the following statements is correct? a. If an equation is dimensionally correct it must be true and if an equation is not dimensionally correct it cannot be true. b. If an equation is dimensionally correct it may be true and if it is not dimensionally correct then it cannot be true. c. If an equation is dimensionally correct it may be true and if an equation is not dimensionally correct it may be true. d. If an equation is dimensionally correct it must be true and if it is not dimensionally correct it may be true.

d. All of these are possible.

Which of these situations is possible? a. Energy is transferred by heat to a system and the internal energy of the system decreases. b. Energy is transferred by heat to a system and the internal energy of the system remains constant. c. Energy is transferred by heat to a system and the internal energy of the system increases. d. All of these are possible.

a). the horizontal component of the normal force

Which one of the following forces holds a car on a frictionless banked curve? a). the horizontal component of the normal force b). the vertical component of the car's weight c). the vertical component of the normal force d). the horizontal component of the car's weight e). the reaction force to the car's weight

c

Which one of the following pictures best represents the forces that prevent the ladder from slipping while someone is standing on it?

a). conservation of kinetic energy

Which one of the following provides a basis to distinguish different types of collisions? a). conservation of kinetic energy b). conservation of mechanical energy c). conservation of impulse d). conservation of linear momentum e). conservation of mass

b). A line that connects a planet to the Sun sweeps out equal areas in the plane of the planet's orbit in equal time intervals.

Which one of the following statements represents Kepler's Second Law? a). In their orbits about the Sun, every planet sweeps out the same equal area in the same equal amount of time. b). A line that connects a planet to the Sun sweeps out equal areas in the plane of the planet's orbit in equal time intervals. c). The surface area of a planet is directly proportional to the square of its orbit about the Sun. d). Every planet sweeps out the same area in a one Earth year period, making one complete orbit about the Sun. e). The area swept by the orbit of the Sun is equal to the sum of the areas swept by the planets during one Earth year period.

b. All objects fall with equal acceleration.

Which one of these laws is not one of Newton's laws? a. Objects at rest stay at rest unless acted on by a force. b. All objects fall with equal acceleration. c. For every action there is an equal and opposite reaction. d. Net Force= mass times acceleration

40% from melting glaciers, 60% from expansion as ocean temperatures rise

Why are sea levels rising?

Because forces are present that cause energy to be lost. Ex: friction

Why can't reversible processes happen in real life?

Because heat naturally flows from high temp to low temp, and that movement of thermal energy is what allows some of it to be turned into mechanical energy

Why do power plants need to be near rivers/lakes?

Metal is actually in thermal eq. with the rest of the room (at the same temperature), as is the book, so they're likely the same temperature. Heat is transferred from your hand to the objects when you touch them. Therefore, the sensation of "coldness" is related to how fast heat is leaving your hand. Metal feels colder because energy is larger - energy is faster to leave your hand. Rate of transfer of conduction depends on the characteristics of the substance.

Why does metal feel colder to the touch than a book?

Because the melting of ocean-based ice won't raise sea levels, because the melted water will only displace as much as the ice already displaces. Level stays the same. Unlike land-based ice, ocean-based ice already displaces water, so when it melts ocean levels won't change much

Why doesn't the melting of ocean-based ice raise as much concern as the melting of land-based ice?

d. remain vertically under the plane.

Without air resistance, an object dropped from a plane flying at the constant speed in a straight line will: a. need more info to answer this question. b. quickly lag behind the plane. c. move ahead of the plane. d. remain vertically under the plane.

How to calculate work done by varying force, given a curve of displacement vs force?

Work done is equal to the area under the curve between xi and xf

a. acceleration is nonzero, but its velocity is zero.

You are throwing a ball straight up in the air. At the highest point, the ball's a. acceleration is nonzero, but its velocity is zero. b. velocity and acceleration are zero. c. velocity is nonzero but its acceleration is zero. d. velocity and acceleration are both nonzero.

a) can the kinetic energy of a system be negative? b) can the gravitational potential energy of a system be negative?

a) no b) yes

as a simple pendulum swings back and forth, the forces acting on the suspended object are the force of gravity, the tension in the supporting cord, and air resistance. a) which of these forces, if any, does no work on the pendulum? b) which of these forces does negative work at all times during its motion? c) describe the work done by the force of gravity while the pendulum is swinging

a) tension in supporting cord b) air resistance always does negative work c) as the pendulum moves to equilibrium (middle), it loses gravitational potential energy and as the pendulum moves away from equilibrium (middle), it gains potential energy. Recall: the work done by gravity is the negative of change in PE

Describe the path of a moving object in the event that the object's acceleration is constant in magnitude at all times and perpendicular to its velocity.

a. If the acceleration is constant in magnitude and perpendicular to the velocity, the object is moving in a circular path at constant speed b. If the acceleration is parallel to the velocity, the object is either speeding up, v and a in the same direction, or slowing down, v and a in opposite directions

a bowling ball is suspended from the ceiling of a lecture hall by a strong cord. the ball is drawn away from its equilibrium position and released from rest at the tip of the demonstrator's nose. if the demonstrator remains stationary, why wouldn't the ball hit her? would she be safe if the ball were given a push from its starting position at her nose?

a. the ball wouldn't hit her because of energy lost to air resistance. if there was no air resistance, it would swing back up to starting position b. probably not, because positive work is done on the ball, and because of that, it will tend to reach a higher level than its initial position before coming to rest again

D. The pressure increasing because more air molecules are striking the walls of the tire.

A girl uses a pump to put air into her bicycle tire at constant temperature. A pressure gauge on the pump indicates the pressure inside the tire is increasing each time she pumps. What is the cause of this pressure increase? A. The air molecules repel each other more as more molecules are added and push outward. B. The volume of the tire is constant. C. The pressure increases to keep the temperature constant. D. The pressure increasing because more air molecules are striking the walls of the tire. E. The pressure increases because the air molecules are traveling faster.

B. It increases.

A hole is drilled in a metal plate. When the metal is raised to a higher temperature, what happens to the diameter of the hole? A. It decreases. B. It increases. C. It remains the same. D. The answer depends on the initial temperature of the metal.

D. difference between the weight of the stone and the weight of the displaced water.

A large aluminum cube in Figure 9.26 a) is resting on the bottom of the tank. The normal force of the bottom of the tank on the cube is equal to the A. weight of the stone. B. weight of the water displaced. C. sum of the weight of the stone and the weight of the displaced water. D. difference between the weight of the stone and the weight of the displaced water.

B. the water line is below the top surface of the Styrofoam.

A lead weight is fastened on top of a large solid piece of Styrofoam that floats in container of water. Because of the weight of the lead, the water line is flush with the top surface of the Styrofoam. If the piece of Styrofoam is turned upside down so that the weight is now suspended underneath it, A. the arrangement sinks. B. the water line is below the top surface of the Styrofoam. C. the water line is still flush with the top surface of the Styrofoam. D. do not have enough information to answer.

B. It will expand as the metallic portion expands.

A metallic key ring of 1.00 cm diameter is placed in a fire and heated up. What would you expect would happen to the inside diameter of the ring as it heats up? A. It will shrink as the metallic portion expands. B. It will expand as the metallic portion expands. C. It will stay the same size as the metallic portion expands. D. It is impossible to say what will happen to the open area in the center of the ring

C. It's because the thermal conductivity of carpet is less than that of tile.

Inside a house, stepping on a tile floor barefooted may feel almost cold, but stepping on carpet in an adjacent room feels comfortably warm. Why is this? A. It's because the tile is below room temperature while the carpet is at room temperature. B. It's because the tile is at room temperature while carpet is normally warmer. C. It's because the thermal conductivity of carpet is less than that of tile. D. It's because the thermal conductivity of tile is less than that of carpet.

B. The loss doubles.

The inside of a house is at 20 °C on an early morning when the temperature outside is 15 °C. The next morning the inside temperature is the same but the outside temperature is now 10 °C. How much does the energy per unit time lost by conduction through the walls, windows, doors, etc., change for the house from the first morning to the second one? A. Since the inside temperature stays the same, the loss is the same both days. B. The loss doubles. C. The loss halves. D. The loss increases by 5/288 since we need to use the Kelvin scale for this calculation.

D. in neither, the flow rate is the same in both pipes

Two pipes are smoothly connected together without leaks. One has a diameter of 3 cm and the other has a diameter of 5 cm. Water flows through the pipes. In which pipe is the volume flow rate the greatest? A. in the pipe that the water flows through first (the "upstream" pipe) B. in the 3-cm pipe C. in the 5-cm pipe D. in neither, the flow rate is the same in both pipes

A. Star A.

Two stars, A and B, have the same emissivity, but the radii and surface temperatures are different with RA = 0.5 RB, and TA = 2 TB. Assuming the temperature of space to be negligible, which star radiates the most energy per unit time? A. Star A. B. Star B. C. Both radiate the same amount of energy per unit time. D. More information is needed in order to make a determination.

Airplane wings aren't flat in order to ensure that the air speed above the wing is greater than the speed below. This makes it so that the air pressure above the wing is less than the air pressure below, which provides a 'lift' force to keep the airplane up. (Net force in the upward direction) In order for a plane to be in level flight, lift on both wings has to support the weight of the plane, so the larger the plane, the larger the area of the wings

Why aren't airplane wings flat? How do we ensure level flight? What is the lift force?

Relates pressure to fluid speed and elevation. Can be used like conservation of ME. Applies to ideal fluids. P + 1/2pv^2 + pgy = constant

What is Bernoulli's equation and why do we care?

All gases extrapolate to the same temperature at zero pressure. This temperature is absolute zero, given by 0K (-273 C).

What is absolute zero?

B. The specific heat is the amount of energy per unit mass to raise the temperature of the object by 1 oC.

Which one of the following statements is the definition of the specific heat of an object? A. The specific heat is the amount of energy per unit mass to raise the temperature of the object from its freezing point to its boiling point. B. The specific heat is the amount of energy per unit mass to raise the temperature of the object by 1 oC. C. The specific heat is the temperature of the object divided by its density. D. Given one gram of the material, the specific heat is the amount of energy to change the material from solid to liquid. E. Given one gram of the material, the specific heat is the amount of energy to change the material from a solid to a gas.

Pressure = Force/Area Force = Area*pressure So to make the net upward force as large as possible, you want the greatest area of the wings

Why do giant planes have giant wings?