physics 221 final

A force F= (4N) i + (3N) j acts on an object at a point located at the position r= (6m)k. What is the torque that this force applies about the origin?

(-18 NxM) i + (18 NxM) j

A container with a piston-lid contains an ideal gas at temperature Ti = 27 oC (300 K) and a volume V0. The temperature is increased to Tf = 127 oC while the pressure is kept constant. What is the new volume?

(4/3) V0

(A) Can two force vectors of unequal magnitude sum to zero net force?(B) Can three force vectors of equal magnitude sum to zero net force?

(A) no, (B) yes

This is the x-t graph for an object moving along the x-axis. Which of the following descriptions of the motion is most accurate?

(Velocity at A) > (Velocity at C) > (Velocity at B)

A block slides on a track from A to B to C to D. The section from A to B to C is frictionless, but for the section from C to D the coefficient of friction is not zero.Is the block's mechanical (ordered) energy increasing, decreasing, or constant in (a) region AB, (b) region BC, and (c) region CD?

(a) constant (b) constant (c) decreasing

An object is dropped from rest at t = 0 into a viscous fluid. Which of the following best describes the object's speed as a function of time?

(b)

The radius of the aorta is ~ 10 mm = 10-2 m and the blood flowing through it has a speed ~ 300 mm/s = 0.3 m/s. A capillary has a radius ~ 4×10-3 mm = 4×10-6 m, but there are literally billions of them. The average speed of blood through the capillaries is ~ 5×10-4 m/s. (i) Calculate the effective cross sectional area of the capillaries and(ii) the approximate number of capillaries.

(i) 0.188 m^2, (ii) 3.75*10^9

For a sound wave of frequency 440 Hz, what is the wavelength(i) in air (propagation speed, v = 3.3 * 102 m/s)?(ii) in water (propagation speed, v = 1.5 * 103 m/s)?

(i) 0.75 m, (ii) 3.41 m

0.5 kg of ice slowly melts. The latent heat of fusion is 80 kcal/kg. By how much does the entropy of the ice change?

+0.147 kcal/K

Suppose a woman does 500 J of work and 9500 J of heat transfer occurs into the environment in the process. What is the decrease in her internal energy, assuming no change in temperature or consumption of food?

-10000 J

A centrifuge in a medical laboratory rotates at an angular speed of 3600 rev/min. When switched off, it rotates 50 times before coming to rest. What is the constant angular acceleration of the centrifuge?

-226.2/s2

A bicyclist starts at point P and travels around a triangular path that takes her through points Q and R before returning to point P. What is the magnitude of her net displacement for the entire round trip?

0

A boy holds a 40 N weight at arm's length for 10 s. His arm is 1.5 m above the ground. The work done by the force of the boy on the weight while he is holding it is

0

The pressure of a gas in a cylinder with a movable piston is increased from 45 kPa to 90 kPa. If the temperature is held constant, and the initial volume of the gas in the cylinder is 0.5 m3, what is the final volume of the gas?

0.25 m^3

Consider a 100 kg father and his 20 kg girl. They decide to enjoy balancing on a seesaw, which is a uniform board 4 m long and pivoted exactly at its center. If girl sits at the seesaw's end (2m from the center), how far from the center on the other side should the father sit?

0.4 m

A DVD is initially at rest so that the line PQ on the disc's surface is along the +x-axis. The disc begins to turn with a constant= 5.0 rad/s2. At t = 0.40 s, what is the angle between the line PQ and the +x-axis?

0.40 rad

Another scheme to catch the roadrunner has failed and a safe falls from rest from the top of a 30.0 m high cliff toward Wile E. Coyote, who is standing at the base. Wile first notices the safe after it has fallen 15 m. How long does he have to get out of the way?

0.72 s

an airplane needs to reach a forward velocity of 203.0 km/hour to take off on a 2000 m runway, what is the minimum uniform acceleration necessary for the plane to take flight if it starts from rest.

0.795 m/s^2

An apple at rest weighs 1 N. Now assume the same apple is in free fall near the surface of Earth. Neglect friction. The net force on the apple while it is in free fall is

1 N

A 170 Hz sound wave in air has a wavelength of 2.0 m. The frequency is now doubled to 340 Hz. What is the new wavelength?

1.0 m

Two masses are located on the x-axis. Mass m1 = 4 kg is located at x = -50 cm and mass m2 = 6 kg is located at x = 20 cm. What is the moment of inertia of the system about the z-axis in units of kgm2.

1.24

A cylinder of gas has a frictionless but tightly sealed piston of mass M. The gas temperature is increased from an initial 27°C to a final 127°C. What is the final-to- initial volume ratio Vf/Vi

1.33

A motor is used to lift an object weighing 15 N a distance of 2 m in 3 seconds. Assuming no conversion of ordered into thermal energy, what is the poweroutput of the motor?

10 W

You live in an apartment directly above an open-air tavern and you possess a really, really long and sturdy straw. You plan to steal beer by leaning out of your apartment window and, when the beer-drinkers are not looking, sticking your straw into beer glasses and sucking on the straw. Assuming you can create a perfect vacuum when you suck on the straw, for this plan to have a chance of working, the height difference between you and the beer must be less than approximately what distance? (Assume the density of beer is equal to the density of water and the pressure is 1 atm = 101 kPa.)

10 m

A race car traveling at a constant speed of 50 m/s drives around a circular track that is 500 m in diameter. What is the magnitude of the acceleration of the car?

10 m/s

An airplane is flying horizontally over level ground. It has an altitude of 500 m and a velocity of 100 m/s. As the airplane passes directly above a cross marked on the ground, an object is released. How far away from the cross will the object land?

1000 m

A 500 N weight sits on the small piston of a hydraulic machine in equilibrium. The small piston has area 2.0 cm2. If the large piston has area 40 cm2, how much weight does the large piston support?

10000 N

the magnitude of the resultant force of all 3 vectors is closest to

13

A football's mass is 0.45 kg. If you did the 60 J of work on the football, while throwing it straight up, how high would it go?

13.3 m

Two blocks of mass M and 3 M are placed on a horizontal frictionless surface. A light spring is attached to one of them, and the blocks are pushed together with the spring between them. A cord holding them together is burned, after which the block of mass 3 M moves to the right with a speed of 5 m/s. What is the speed of the block of mass M?

15 m/s to the left

A 1200 kg car's speed changes from 5 m/s to 20 m/s in 4 s. By what factor does its kinetic energy change during those 4 s.

16

The pilot of a light airplane with an airspeed of 200 km/h wants to fly due west. There is a strong wind of 120 km/h blowing from the north. If the pilot points the nose of the airplane north of west so that her ground track is due west, what will be her ground speed?

160 km/h

During one cycle, an automobile engine with an efficiency of 20% takes in 10,000 J of heat. How much work does the engine do per cycle?

1600 J

Suppose you are changing a car tire and loosening a lug nut. You weigh 800 N and stand on the end of a horizontal 2 m long wrench. How much torque do you exert on the lug nut?

1600 Nm

A cheerleader lifts his 50 kg partner three times straight up off the ground a distance of 1.1 m before releasing her. How much work does he do lifting her 3 times? Use g = 10 m/s2.

1650 J

You hear the sound of the ring of a distant cannon 5 seconds after seeing the flash. How far are you from the cannon?

1700 m

A 2 kg block of wood is floating in water. What is the magnitude of the buoyant force acting on the block?

19.6 N

A bicycle's wheels have a radius of 33 cm. The bicycle is traveling at a speed of 6.5 m/s. What is the angular speed of the front tire?

19.7 rad/s

A 1 kg rock is suspended by a massless string from one end of a meter stick at the 0 cm mark. What is the mass m suspended from the meter stick at the 75 cm mark if the system is balanced?

2 kg

Suppose the circumference of a bicycle wheel is 2 m. If it rotates at 1 revolution per second when you are riding the bicycle, then your speed will be

2 m/s

A fan rotating with an initial angular velocity of 1000 rev/min is switched off. In 2 seconds, the angular velocity decreases to 200 rev/min. Assuming the angular acceleration is constant, how many revolutions does the blade undergo during this time?

20

a sound of 40 decibels is

20 dB is 100x the power

A ball (mass 0.40 kg) is initially moving to the left at 30 m/s. After hitting the wall, the ball is moving to the right at 20 m/s. What is the impulse of the net force on the ball during its collision with the wall?

20 kg • m/s to the right

Christina throws a javelin into the air. As she propels it forward from rest, she does 270 J of work on it. At its highest point, its gravitational potential energy has increased by 70 J. What is the javelin's kinetic energy at this point?

200 J

a football kicker is attempting a field goal from 44m out. The ball is kicked and just clears the lower bar with a time flight of 2.9s. If the angle of the kick was 45, what was the initial speed of the ball?

21.59 m/s

Suppose the nose of an airplane is pointed due east and the airplane has an airspeed of 150 km/h. Due to the wind, the airplane is moving due north relative to the ground and its speed relative to the ground is 150 km/h. What is the velocity of the air relative to the earth?

212 km/h

A block with a weight of 2 N slides across a flat surface with a speed of 15 m/s. What is the kinetic energy of the block?

22.5 J

During one cycle, an automobile engine takes in 12,000 J of heat and discards 9000 J of heat. What is the efficiency of this engine?

25%

Blood is pumped from the heart at a volume flow rate of 5.0 liter/min into the aorta (of radius 1.0 cm). Determine the speed of blood through the aorta.

26.5 cm/s

What is the net power needed to change the speed of a 1600 kg sport utility vehicle from 15.0 m/s to 40.0 m/s in 4s.

275 KW

A 750 kg automobile is traveling horizontally with speed 20.0 m/s. What is the automobile's new speed after an additional 150000 J of net work has been done on the car?

28.3 m/s

A standing wave is established on a 1.2 m long string fixed at both ends. The string vibrates in four segments when driven at 120 Hz. What is the fundamental frequency?

30 Hz

A girl pulling a sled exerts a 20 N force horizontally for 40 s. How much power does she generate while moving the sled 60 m?

30 W

With the temperature held constant, the piston of a cylinder containing a gas is pulled out so that the volume increases from 0.1 m3 to 0.3 m3. If the pressure of the gas was 90 kPa, what is the final pressure?

30 kPa

A machine uses 1000 J of electric energy to raise a heavy mass, increasing its potential energy by 300 J. What is the efficiency of this process?

30%

Substance A has a density of 3.0 g/cm3 and substance B has a density of 4.0 g/cm3. In order to obtain equal masses of these two substances, the ratio VA/VB of the volume of A to the volume of B has to be equal to

4 : 3

A stationary source S generates circular outgoing waves on a lake. The wave speed is 5.0 m/s and the crest-to-crest distance is 2.0 m. A person in a motorboat heads directly toward S at 3.0 m/s. To this person, the frequency of these waves is:

4 Hz

In the cyclic process on an ideal gas shown in the adjoining PV diagram, what is the net work done by the gas during the cycle?

4 PV

a chicken is running in a circular path with a angular speed of 1.52 rad/s. How long does it take the chicken to complete 1 rev?

4.13 s

A person walks first at a constant speed of 6 m/s along a straight line from point A to point B and then back along the line from B to A at a constant speed of 4 m/s. What is her average speed over the entire trip?

4.8 m/s

You operate a 120 W light bulb for 1 hour. How much energy did you use? (1 W = 1 J/s)

432000 J

Mercury has an unusually large surface tension γ = 0.465 N/m. Calculate the excess pressure inside a drop of mercury 4 mm in diameter.

465 Pa

A Carnot engine takes heat in from a reservoir at 400 K and discards heat to a reservoir at 300 K. If the engine does 12,000 J of work per cycle, how much heat does it take in per cycle?

48,000 J

a bullet shot straight up returns to its starting point in 10s. What is the initial speed of the bullet, assuming negligible air resistance?

49 m/s

An object rotates initially with a period of 1.0 s. It accelerates with constant angular acceleration for 10 s. Its final rotation period is 0.1 s.What was the magnitude of its angular acceleration?

5.65 rad/s^2

a light year is the distance that light travels in 1 year. The speed of light is 3.0 x 10^8 m/s. How many miles are there in a light year?

5.88 x 10^12

How much heat transfer occurs from a system if its internal energy decreased by 150 J while it was doing 100.0 J of work?

50J

A CD spins at 5500 rpm (revolutions per minute). What is its angular speed in units of rad/s or s-1?

576

an astronaut weighs 99N on the moon, where the acceleration of gravity is 1.62 m/s^2. How much does she weigh on earth?

598.88 N

the acceleration due to gravity on the moon is 1/6 of earths, and the moon has no atmosphere. If you hit a baseball on the moon with the same effort as on earth, how far would the ball travel on the moon compared to the earth?

6 times as far as on earth

A 50 kg woman balances on one heel of a high-heel shoe. If the heel is circular with radius 0.5 cm, what pressure does she exert on the floor?

6.2 MPa

A boy throws a 0.1 kg ball from a height of 1.2 m to land on the roof of a building 8 m high. What is the potential energy of the ball on the roof relative to its starting point?

6.67 J

A 2 kg mass is at x = 0 m, y = 2 m, and a 3 kg mass is at x = 2 m, y = 0 m. The x- and y-coordinates, respectively, of the center of mass of this system are

6/5 m, 4/5 m

A train whistle is blown by the driver who hears the sound at 650 Hz. If the train is heading towards a station at 20.0 m/s, what will the whistle sound like to a waiting commuter? Take the speed of sound to be 340 m/s.

691 Hz

You are bored during the summertime when school is not in session and you decide to do an experiment where you compare the properties of water and air. If the density of air is 1.25 kg/m3 and the density of water is 1000 kg/m3, what volume of air weighs the same as 1 liter (10-3 m3) of water?

800 liters

The diameter of a pipe is tripled while the pressure difference across the pipe remains the same. The volume flow rate of the pipe increases by a factor of

81

A sealed cubical container, 20 cm on a side, contains 3 times Avogadro's number of molecules at a temperature of 20 oC. What is the pressure in the container? (1 atm = 101 kPa)

9 atm

Two children pull a sled as shown. The sled moves with constant velocity v. Find the frictional force on the sled.

90.6 N

Fluid is flowing from left to right through the pipe. Points A and B are at the same height, but the cross-sectional areas of the pipe differ. Points B and C are at different heights, but the cross-sectional areas are the same. Rank the pressures at the three points, from highest to lowest.

A, B, C

The following pairs of temperatures represent the temperatures of hot and cold reservoirs for heat engines. Which heat engine has the highest possible efficiency?

A. 300°C, 30°C

A block of ice (density 920 kg/m3), a block of concrete (density 2000 kg/m3), and a block of iron (density 7800 kg/m3) are all submerged in the same fluid. All three blocks have the same volume. Which block experiences the greatest buoyant force?

All three experience the same buoyant force.

Three trajectories labeled A, B, and C are shown below. For which trajectory is the vertical velocity component at launch the greatest?

All three trajectories have the same initial vertical velocity component at launch.

A ball is fired by a cannon from the top of a cliff as shown in the figure below. Which of the path would the cannonball most closely follow?

B

Two pitchers are standing side by side, and simultaneously throw baseballs A and B. The balls follow the parabolic trajectories shown. Which of the following statements is true?

Ball B his the ground before ball A

1 kg of silver (c = 234 J/kg K) is heated to 100°C. It is then dropped into 1 kg of water (c = 4190 J/kg K) at 0°C in an insulated beaker. After a short while, the common temperature of the water and silver is

Between 0°C and 50°C

The picture below shows 5 blocks. The blocks have equal volumes but different masses. The blocks are placed in an aquarium tank filled with water and blocks 2 and 5 come to rest as shown in the figure.

Block 3 will come to rest in the same position as block 5.

A 3.00-kg rifle fires a 0.00500-kg bullet at a speed of 300 m/s. Which force is greater in magnitude: the force that the rifle exerts on the bullet or the force that the bullet exerts on the rifle?

Both forces have the same magnitude.

You drop an object from a bridge and simultaneously, you throw a-other object downwards at 10 m/s. As the objects are falling, which object has the larger acceleration? (Ignore air resistance.)

Both objects have the same acceleration.

You need to loosen a very tight bolt. You have one wrench and you exert maximum force. Which configuration shown below gives you maximum chance of success?

C

Car #1 is going 50 mi/h when it crashes into a stationary wall and comes to a halt. An identical car #2 is going 50 mi/h when it crashes head-on into, and sticks to, identical car #3 going 50 mi/h in the opposite direction. Which statement is correct?

Car #1 loses the same amount of momentum and the same kinetic energy in its collision as does car #2.

Car 1 starts from rest along a straight highway with constant acceleration a = 1 m/s2. Car 2 passes car 1 with constant velocity of 120 km/hr. Which car is acted on by a larger net force?

Car 1

Bob and Carl are riding on a merry-go-round. Bob is closer to the center of the merry-go-round. Who has the greater centripetal acceleration?

Carl

When a sample of 0 C water is heated, it first

Contracts then expands.

An object moves with constant speed in the clockwise direction along the circular path shown below.At the point indicated by the black dot, in which direction is the angular velocity vector ω pointing?

D (towards the center)

Modeling a meter stick as a forearm, compare the force FB that the biceps has to exert to keep the forearm horizontal to the weight of the forearm FW = mg. Let d = 10 cm and the distance from where the biceps muscle attached to the center of mass be d' = 40 cm.

FB = 5 mg

In soap box car races, the cars are boxes with wheels. They begin at rest at the top of a hill, and at the start of the race they all begin rolling down the hill. The soap box car that reaches the bottom of the hill first is the winner. You have entered a soap box car race where the rule is that all the wheels and cars must have equal mass. Since you have taken Physics, you know that it is worse to have wheels with spokes (where the mass is mostly on the rim) rather than solid wheels because

Given the same torque, the wheels with spokes have a higher rotational mass or moment of inertia and therefore will have a smaller angular acceleration.

Consider two masses, each of size 2m at the ends of a light rod of length L with the axis of rotation through the center of the rod. The rod is doubled in length and the masses are halved. Compare IA and IB.

IA < IB

A sample of nitrogen gas is inside a sealed container. The container is slowly compressed, while the temperature is kept constant. This is a ........................process.

Isothermal

A child is riding a bike and skids to a stop. What happens to their kinetic energy?

It is converted into thermal energy.

A copper pot at room temperature is filled with room-temperature water. Imagine a process whereby the water spontaneously freezes and the pot becomes hot. Why is such a process impossible?

It violates both the first and second laws of thermodynamics

A car's speed changes from 20 mph to 60 mph. By what factor does its kinetic energy change?

It will increase by a factor of 9.

Block A on the left has mass 1.00 kg. Block B on the right has mass 3.00 kg. The blocks are forced together, compressing the spring. Then the system is released from rest on a level, frictionless surface. After the blocks are released, how does KA (the kinetic energy of block A) compare to KB (the kinetic energy of block B)?

KA = 3KB

A spinning figure skater pulls his arms in as he rotates on the ice. As he pulls his arms in, what happens to his angular momentum L and kinetic energy K?

L stays the same; K increases.

A clever physics student is able to sneak a scale on a popular ride at an amusement park. Before the ride begins to move, the scale reads 700 N for the student's weight. As the ride lifts, it initially accelerates upward at 3 m/s2. At the top, the riders are held in suspense before the gondola is allowed to free fall downward with acceleration equal to g. What should the scale read for the student's apparent weight during the lift and the fall?

Lift: 910N, Fall: 0 N

Consider two projectiles that can be shot upward by spring guns from ground level. Object A is made of solid aluminum and has a mass of 50 grams. Object B is made of cast iron and has a mass of 200 grams. Masses A and B are both shot straight upward at the same time. Mass A is shot with a speed of 2 m/s and mass B with a speed of 1 m/s. Which one hits the ground first?

Mass B

Consider the earth spinning from west to east on its axis. It is slowing down in its rotation due to friction with the air. Using the right hand rule, in what direction is the frictional torque?

N pole to S pole

Two objects with different masses collide with and bounce off each other. Compared to before the collision, the system of two objects after the collision has

Not enough information is given to decide

two moving objects have masses m1 and m2, respectively. If m2 = 4m1, and both have the same kinetic energy, which has more momentum?

Object 2 with mass m2

The three objects shown here all have the same mass and the same outer radius. Each object is rotating about its axis of symmetry (shown in blue). All three objects have the same rotational kinetic energy. Which object is rotating fastest?

Object B is rotating fastest.

Which of the following statements is false?

Plaque deposit on an artery or arteriole wall causes an increase in local blood pressure and can lead to bursting of that vessel.

This is the x-t graph of the motion of a particle. Of the four points P, Q, R, and S, the velocity vx is greatest (most positive) at

Point P

This is the x-t graph of the motion of a particle. Of the four points P, Q, R, and S, the speed is greatest at

Point R

This is the x-t graph of the motion of a particle. Of the four points P, Q, R, and S, the acceleration ax is greatest (most positive) at

Point S

A DVD is rotating with an ever increasing speed. How do the angular velocity, angular acceleration, tangential velocity, and tangential acceleration compare at points P and Q?

Points P and Q have the same angular velocity and the same angular acceleration.

In a stationary homogeneous liquid near the surface of Earth, which of the following is true?

Pressure is the same at all points at the same height

In the constellation Orion, you can easily observe the difference between the reddish looking star Betelgeuse and the bluish looking star Rigel. Which of the two has the hotter surface temperature?

Rigel

A cart (weight w1) is attached by a lightweight cable to a bucket(weight w2) as shown. The ramp is frictionless. The pulley is frictionless and does not rotate. When released, the cart accelerates up the ramp and the bucket accelerates downward. How does the cable tension T compare to w2?

T < w2

On a humid summer day, perspiration does not cool you off much. Why?

The air is almost saturated with water vapor and there is almost no net evaporation.

A pitcher contains 0.50 kg of liquid water at 0°C and 0.50 kg of ice at 0°C. You let heat flow into the pitcher until there is 0.75 kg of liquid water and 0.25 kg of ice. During this process, the temperature of the ice-water mixture

The answer depends on the rate at which heat flows.

When the temperature of an ideal gas is increased, which of the following also increases?

The average kinetic energy of the gas atoms

Suppose Larissa throws a ball up in the air and it comes back down to the same place she threw it from. Ignore the times when the ball is in contact with her hand, and ignore air resistance.

The ball has minimum kinetic and maximum potential energy at maximum height.

A block and a rod are joined together. Each object is of uniform density. The center of mass of the combined object is at the position shown by the "X."Which has the greater mass, the block or the rod?

The block has the greater mass.

An elevator is being lowered at a constant speed by a steel cable attached to an electric motor. Which statement is correct?

The cable does negative work on the elevator, and the elevator does positive work on the cable.

An elevator is being lifted at a constant speed by a steel cable attached to an electric motor. Which statement is correct?

The cable does positive work on the elevator, and the elevator does negative work on the cable.

A bullet is fired horizontally from a rifle on the Moon (no air, g = 1.6 m/s2) with initial speed v0. Assuming a level and endless ground, which statement is false?

The flight time increases as v0 increases

An ideal, non-compressible fluid is used in the system of pipes shown below. The cross sectional area of pipe 1 is 4 m2, that of pipe 2 is 3 m2, and that of pipe 3 is 2 m2. The fluid enters pipe 1 at 2 m/s, and leaves pipe 2 at 3 m/s. What is the speed of the fluid in pipe 3 and in which direction does it flow?

The fluid leaves pipe 3 (downward) with speed 0.5 m/s.

A horse is hitched to a wagon. Which statement is correct?

The force that the horse exerts on the wagon is just as strong as the force that the wagon exerts on the horse.

Consider a marble rolling around in a bowl sitting on a table on Earth. Neglect friction. Which of the following statements is true?

The gravitational potential energy of the marble depends on the choice of the reference position for zero potential energy.

You are testing a new car using crash test dummies. Consider two ways to slow the car from 90 km/h (56 mi/h) to a complete stop:

The impulse is the same in both cases.

A box is at rest on a flat table. Which of the following is true?

The normal force and the gravitational force are equal in magnitude and opposite in direction.

An object moves in a circle with constant speed

The object is accelerating. It is acted on by a radial force, pointing towards the center of the circle

If the net work done on an object is negative, which of the following statements must be true?

The object loses kinetic energy

A force of 20 N in the positive x‐direction accelerates an object giving it a = 2 m/s2. When the object is moving with velocity v = 10 m/s, an additional force of 10 N in the negative x‐direction is applied. Which statement is true?

The object now accelerates with acceleration a = 1 m/s2 in the positive x‐direction.

A train sounding its horn is approaching an observer.

The pitch of the horn's sound relative to its normal pitch is higher.

You immerse a 1-kg block of iron in 1 kg of water in an insulated chamber, add 100 J of heat, and allow the iron and water to equilibrate to the same temperature. Which has absorbed more heat, the iron or the water?

The water absorbs more heat.

You throw a ball straight up. Compare the sign of the work done by the force of gravity while the ball goes up with the sign of the work done by gravity while it goes down.

The work done by the force of gravity is negative on the way up and positive on the way down.

Which of the following assumptions is not made in the derivation of Bernoulli's equation?

There is negligible gravity.

You drop a ball from rest and simultaneously shoot a second, identical ball horizontally from the same height as the first ball. If there is no air resistance, which ball hits the ground first?

They both hit at the same time.

Why do elastic balls bounce so well?

They store energy through compression, like a spring.

The graph shows the net force acting on an astronaut during a rocket launch into a stable orbit. During which time interval was the acceleration of the rocket the greatest?

U-V

Your dryer is broken, so you have to hang your wet clothes from the washing machine outside to dry. Under which conditions would your clothes dry fastest?

When it is 75°F with 50% relative humidity.

If a cyclist is going around a curve at constant speed, is he accelerating? If so, what is the direction of his acceleration?

Yes, he is accelerating toward the inside of the curve.

Suppose you are on a cart, initially at rest on a frictionless, horizontal track. You throw a series of identical balls against a wall that is rigidly mounted to the cart. If the balls are thrown at a steady rate and bounce straight back, is the cart put into motion?

Yes, it starts to move to the left and steadily gains speed.

In which of these situations would the average velocity vector over an interval be equal to the instantaneous velocity at the end of the interval?

a body moving along a straight line at constant speed

Suppose you work in the E.R. and a choking patient comes in with their trachea half obstructed. (The diameter is half of what it was before the obstruction.) You manage to correct the problem and send them on their way safely, explaining that such obstructions are particularly dangerous because

a half - blocked airway passes only 1/16 the regular amount of air.

On a day when there is no wind, you are at rest and a source of sound waves is moving toward you. Compared to what you would hear if the source were not moving, the sound that you hear has

a higher frequency and a shorter wavelength.

On a day when there is no wind, you are moving toward a stationary source of sound waves. Compared to what you would hear if you were not moving, the sound that you hear has

a higher frequency and the same wavelength.

An incompressible fluid with zero viscosity flows through a pipe of varying radius (shown in cross- section). Compared to the fluid at point P, the fluid at point Q has

a lower pressure and the same volume flow rate

Work, as defined in physics is

a scalar quantity, a positive or negative number with units.

As a sound source moving with constant velocity approaches and then moves past a stationary observer, the observer will hear

a sudden drop in pitch

The shape of a droplet of liquid on a surface is due to a combination of

adhesion and cohesion

The vessels shown below all contain water to the same height.Rank them according to the pressure exerted by the water on the vessel bottoms, least to greatest.

all pressures are the same

Which sounds travel the fastest through air?

all sound travels at the same speed through air

A star with a surface temperature of 6000 K appears yellow in color. A star with a surface temperature of 4000 K will

appear reddish on color

The left tip of a wind turbine blade accelerates upward, as you view it. By the right-hand rule, the torque on the wind turbine is pointing

away from you.

The interference of two sound waves of similar amplitude but slightly different frequencies produces a loud-soft-loud oscillation we call

beats

Blocks A and C are connected by a string as shown. When released, block A accelerates to the right and block C accelerates downward. There is friction between blocks A and B, but not enough to prevent block B from slipping. If you stood next to the table during the time that block A is accelerating to the right and block B is slipping on top of block A, you would see

block B accelerating to the right.

Living cells constitute a low entropy state of matter. Living cells

can exist because they help increase the entropy of the rest of the universe.

Increasing the pressure amplitude of a sound wave by a factor of 4 (while leaving the frequency unchanged)

causes the intensity to increase by a factor of 16

The first law of thermodynamics is a re-statement of the law of

conservation of energy

When you first step out of a swimming pool on a warm day, you feel cool. This is due primarily to

convection

A lightweight crate (A) and a heavy crate (B) are side-by-side on a horizontal floor. You apply a horizontal force F to crate A. There is friction between the crates and the floor. If the two crates are accelerating to the right,

crate A exerts as much force on crate B as B exerts on A.

a bimetallic strip, consisting of metal G on the top and metal H on the bottom, is rigidly attached to a wall at the left. The coefficient of linear thermal expansion for metal G is greater than that of metal H. If the strip is uniformly heated it will...

curve downward

A 100 Hz sound wave is traveling through the air. If we increase the frequency to 200 Hz, this will Fill in the blank the wavelength.

decrease

A grandfather clock is running slow. The period of its pendulum is too long. To shorten the period and make the clock run faster, you should.

decrease the length of the pendulum

A pendulum of length L is suspended from the ceiling of an elevator. When the elevator is at rest the period of the pendulum is T. How does the period of the pendulum change when the elevator moves upward with constant acceleration?

decreases

A simple pendulum consists of a point mass suspended by a massless, unstretchable string. If the mass is doubled while the length of the string remains the same, the period of the pendulum

decreases

A skier skis in a straight line down a hill gradually picking up speed as he goes. Which of the following could plausibly be an external force diagram for the skier during this motion? Assume air resistance is negligible.

diagram d

The entropy of an isolated system

either increases or remains constant

A boat is floating in a lake. Since it is floating the buoyant force acting on the boat must be

equal to its weight

A rock is thrown from the roof of a tall building.While it is falling towards the ground, the force of gravity acting on it is

equal to its weight

An elevator is being lifted at a constant speed by a steel cable attached to an electric motor. There is no air resistance, nor is there any friction between the elevator and the walls of the elevator shaft. The upward force exerted on the elevator by the cable is

equal to the force of gravity

An elevator is being lowered at a constant speed by a steel cable attached to an electric motor. There is no air resistance, nor is there any friction between the elevator and the walls of the elevator shaft. The upward force exerted on the elevator by the cable is

equal to the force of gravity.

in an isothermal expansion of an ideal gas, the amount of heat that flows into the gas

equals the amount of work done by the gas.

Suppose you take off in a car with your physics book on top. If you are accelerating forward and the book rides with you, in what direction does friction act on the book?

forwards

An incompressible fluid with zero viscosity flows through a pipe of varying radius (shown in cross- section). Compared to the fluid at point P, the fluid at point Q has

four times the fluid speed.

When a hot cup is filled with cold water, the direction of heat flow is

from the cup to the water

A sample of a low-density gas is initially at room temperature and has pressure P0. The gas is warmed at constant volume until the pressure is 2P0. Compared to the initial Celsius temperature of the gas, the final Celsius temperature is

greater by a factor of more than 2

A sample of a low-density gas is initially at room temperature and has pressure p0. The gas is warmed at constant volume until the pressure is 2p0. Compared to the initial Celsius temperature of the gas, the final Celsius temperature is

greater by a factor of more than 2.

An ideal gas begins in a thermodynamic state a. When the temperature of the gas is raised from T1 to a higher temperature T2 at a constant volume, a positive amount of heat Q12 flows into the gas. If the same gas begins in state a and has its temperature raised from T1 to T2 at a constant pressure, the amount of heat that flows into the gas is

greater than Q12.

Two blocks are connected as shown. The rope and pulley are of negligible mass. When released, the block of mass m1 slides down the ramp and the block of mass m2moves upward. After each block has moved a distance d, the total work done on m1 is

greater than the total work done on m2.

Two blocks are connected as shown. When released, the 6.00-kg block accelerates downward and the 8.00-kg block accelerates to the right. After each block has moved 2.00 cm, the total work done on the 8.00-kg block is

greater than the total work done on the 6.00-kg block

You want to double the radius of a rotating solid sphere while keeping its kinetic energy constant. (The mass does not change.) To do this, the final angular velocity of the sphere must be

half of its initial value

Suppose you have two containers with liquid in them. One has a density of 760 kg/m3 and the other has a density of 910 kg /m3. If an object floats in one container and sinks in the other, the density of the object

has a value between 760 kg/m3 and 910 kg/m3.

Increasing the frequency of a sound wave by a factor of 4 (while leaving the pressure amplitude unchanged)

has no effect on the wave intensity.

A woman exerts a constant horizontal force on a large box. As a result, the box moves across a horizontal floor at a constant speed v0. The constant horizontal force supplied by the woman

has the same magnitude as the total force which resists the motion of the box.

During a football game the ball is kicked and it travels across the field. If the ball is kicked away from its center of mass it will

have translational and rotational motion.

A chair has a wooden seat but metal legs. The chair legs feel colder to the touch than does the seat. Why is this?

he metal has a lower thermal conductivity than the wood.

A heat engine extracts usable work by permitting

heat to flow from a hotter object to a colder object.

A man, with his arms at his sides, is spinning on a light frictionless turntable. When he extends his arms

his angular momentum remains the same.

Flowing honey is less likely to become turbulent than flowing water because

honey's large viscosity favors laminar flow

You paddle in a Kayak across a calm mountain lake. Each time you pull the paddle backward through the water, from the front of the boat to its rear, the water exerts a force on the paddle that is

in the forward direction, towards the front of the boat.

A steady force pushes in the piston of a well-insulated cylinder. In this process, the temperature of the gas

increases

A cylinder is completely filled with water. The top of the cylinder is sealed with a tight-fitting lid. If you push down on the lid with a pressure of 1000 Pa, the water pressure at the bottom of the cylinder

increases by 1000 Pa

If a viscous fluid flows steadily in a pipe, the fluid speed

is least near the pipe wall but increases toward the center.

A cylinder of gas has a frictionless but tightly sealed piston of mass M. A small flame heats the cylinder, causing the piston to slowly move upward. For the gas inside the cylinder, what kind of process is this?

isobaric

At constant pressure, the volume of a gas sample is directly proportional to

its absolute temperature

You toss a ball straight upward, in the positive direction. The ball falls freely under the influence of gravity. At the highest point in the ball's motion

its velocity is zero and its acceleration is negative (downward)

The SI units for viscosity are

kg/(m-s)

the distance d through which a beam of length L is deflected when is is subjected to a fixed load and may be described by the relationship d=RL^2. What are the SI units of the constant R?

length^-1

When an ideal gas is allowed to expand isothermally from volume V1 to a larger volume V2, the gas does an amount of work equal to W12. If the same ideal gas is allowed to expand adiabatically from volume V1 to a larger volume V2, the gas does an amount of work that is

less than W12

Two liquids, A and B, have equal masses and equal initial temperatures. Each is heated for the same length of time over identical burners. Afterward, liquid A is hotter than liquid B. Which has the larger specific heat?

liquid B

Sound waves are...

longitudinal waves

Water pours gently from an open hose because it

lost energy throughout its trip to the hose end.

ball is released form rest on a non-slip surface. After reaching its lowest point, the ball begins to rise again, this time on a frictionless surface. When the ball reaches its maximum height on the frictionless surface it is

lower than when it was released

The volume of a gaseous sample is increased from V1 to V2 in three different ways. A-->B: isobaric process A-->C: isothermal process A-->D: adiabatic process Then the work done by the gas is

maximum in the isobaric process

In the absence of air resistance, a ball of mass m is tossed upward to reach a height of 20 m. At the 15 m position, 3/4 of the way up, the net force on the ball is

mg

A projectile is launched at a 30° angle above the horizontal. Ignore air resistance. The projectile's acceleration is greatest

misleading question—the acceleration is the same (but nonzero) at all points along the trajectory

The quantities remain constant in an inelastic collision are

momentum, but neither kinetic energy nor temperature.

A nonzero net force acts on an object. Which of the following quantities could be constant?

more than one of A, B, and C

A cable attached to a car holds the car at rest on the frictionless ramp (angle ). The ramp exerts a normal force on the car. How does the magnitude n of the normal force compare to the weight w of the car?

n < w

A toboggan of weight w (including the passengers) slides down a hill of angle at a constant speed. Which statement about the normal force on the toboggan (magnitude n) is correct?

n < w

An ice-cube sits in a bath of water. The water, the ice and the surrounding air are all at 0 C. Does heat enter the ice cube?

no

An ice‐cube sits in a bath of water. The water, the ice and the surrounding air are all at 0 C. Does heat enter the ice cube?

no

Is it possible to cool down a well insulated room on a hot summer day by leaving the refrigerator door open, and using the refrigerator as an air conditioner?

no

Joel and Jerry push against a car that has stalled, trying unsuccessfully to get it moving. Jerry stops after 10 min, while Joel is able to push for 5.0 min longer. Compare the work they do on the car?

no work is done

A point on a standing wave that is always stationary is a.............

node

Block A has mass 1.00 kg and block B has mass 3.00 kg. The blocks collide and stick together on a level, frictionless surface. After the collision, the kinetic energy (KE) of block A is

one-third the KE of block B.

Block A on the left has mass 1.00 kg. Block B on the right has mass 3.00 kg. The blocks are forced together, compressing the spring. Then the system is released from rest on a level, frictionless surface. After the blocks are released, how does pA (the magnitude of momentum of block A) compare to pB (the magnitude of momentum of block B)?

pA = pB

Two cylinders, A and B, contain the same type of gas at the same temperature. Cylinder A has twice the volume as cylinder B and contains half as many molecules as cylinder B. Which is true?

pA = pB /4

A girl attaches a rock to a string, which she then swings counter-clockwise in a horizontal circle. The string breaks at point P in the figure, which shows a bird's-eye view (as seen from above). Which path (A-E) will the rock follow?

path B

Rockets receive their forward propulsion through

pushing against the exhuast

Which type of heat transfer can happen efficiently through empty space?

radiation

People fighting forest fires carry emergency tents that have shiny aluminum outer surfaces. If there is trouble, a fire fighter can lie under the tent to block the heat from burning trees overhead. The tent helps because

radiation carries heat downward toward the fire fighter and the aluminum tent reflects most of that radiation.

An object is dropped from an airplane flying at a constant speed in a straight line at a constant altitude. If there is no air resistance, the falling object will (as seen from the ground)

remain directly under the airplane

A refrigerator

removes heat from a cold region and delivers the more heat to a hotter region.

When stringing telephone lines between poles in the summer, it is advisable to allow the lines to

sag

A skater who is spinning and throws her arms out slows down because

she makes her rotational mass or moment of inertia bigger.

The velocity and acceleration of an object at a certain instant are v= (3.0 m/s) j a= (0.5 m/s^2) i - (0.2m/s^2) j At this instant, the object is

slowing down and following a curved path.

The velocity and acceleration of an object at a certain instant are v= (2.0 m/s^2) i + (3.0 m/s) j a= (0.5 m/s^2) i - (0.2 m/s^2) j

speeding up and following a curved path.

If you toss a ball upward with a certain initial speed, it falls freely and reaches a maximum height h. By what factor must you increase the initial speed of the ball for it to reach a maximum height 3h?

srt 3

Which of the following statements about distance and/or displacement are TRUE? (1) Distance is a vector quantity and displacement is a scalar quantity. (2) If a person walks in a straight line and never changes direction, then the distance and the magnitude of the displacement are exactly the same. (3) The diagram below depicts the path of a person walking from position A to B back to C to and then to D. The distance traveled is 90 yds. (4) For the same diagram below, the displacement of the person walking from A to B to C to D is 50 yds.

statements 2 and 3

Two cars move towards each other on a frictionless road as shown in the sketch below. The two cars collide and immediately come to a standstill. During the collision, the total momentum of the two vehicles will

stay constant

Two objects in thermal equilibrium have the same

temperature

a rock from a volcanic explosion is launched straight up into the air w/ no approachable air resistance, which statement is correct while the rock is in the air?

the acceleration is downward at all the points in motion

suppose that a car is traveling to the west begins to slow down as it approaches a traffic light. Which of the following statements about its acceleration is correct?

the acceleration is towards the east

When you blow some air above a paper strip, the paper rises. This happens because

the air above the paper moves faster and the pressure is lower

One kilogram of iron (density ~7.8 gm/cm3) and 1 kilogram of aluminum (density ~2.7 gm/cm3) are dropped into a pool. Which is acted on by the largest buoyant force?

the aluminum

Your hands push on a heavy box to slide it across the floor with constant velocity. The other force of the action/reaction pair is

the box pushing backward against your hands.

When you sit facing a campfire outdoors, your face feels quite warm because

the campfire is radiating heat towards your skin.

It is correct to say that impulse is equal to

the change in momentum

The illustration shows a thermometer that uses a column of liquid (usually mercury or ethanol) to measure air temperature. In thermal equilibrium, this thermometer measures the temperature of

the column of liquid. the glass that encloses the liquid the air outside the thermometer.

As I apply the brakes in my car, books on the passenger seat suddenly fly forward. That is most likely because

the decelerating car is not an inertial reference frame.

No work is done by gravity on a bowling ball that rolls along a bowling alley because

the force of gravity is perpendicular to the balls velocity,

You are walking on a level floor. You are getting good traction, so the soles of your shoes don't slip on the floor. Which of the following forces should be included in a free-body diagram for your body?

the force of static friction that the floor exerts on your shoes

You are standing at rest and begin to walk forward. What force pushes you forward?

the force of the ground on your feet

a 20 ton truck collides w/ a 1500 lb car. Which of the following statements must be true?

the force on the truck due to collision is exactly equal to the force on the car

After clearing the bar on a high jump, you land softly on a giant mattress. Landing on a mattress is more comfortable than landing on a sand heap of equal size because

the force the mattress exerts on you to stop your descend is much less than the force the sand heap would exert on you.

A solid bowling ball rolls down a ramp. Which of the following forces exerts a torque on the bowling ball about its center?

the friction force exerted by the ramp

While an object is in projectile motion (with upward being positive) with no air resistance,

the horizontal component of its velocity remains constant and the vertical component of its acceleration is equal to -g.

An open cart is rolling to the left on a horizontal surface. A package slides down a chute and lands in the cart. Which quantity or quantities have the same value just before and just after the package lands in the cart?

the horizontal component of total momentum

When a gas expands adiabatically,

the internal thermal energy of the gas decreases

a spherical ball of lead is placed in a tub of mercury. Which answer best describes the result?

the lead ball will float with about 17% of its volume above the surface of the mercury

The longer the wavelength of a sound wave

the lower is its pitch

It is possible for two objects of equal mass to have different moments of inertia about the same axis because

the moment of inertia depends on the total mass and the mass distribution.

Consider a car at rest. We can conclude that the downward gravitational force Earth exerts on the car and the upward contact force the surface of Earth exerts on the car are equal in magnitude and opposite in direction because

the net force on the car at rest is zero

If you dangle two pieces of paper vertically a few inches apart and blow air between them

the papers will move together because the increased velocity reduces the pressure between the papers.

At a compression in a sound wave,

the particle displacement is 0

The maintenance of the life cycle depends on

the presence of a source and a sink of energy.

Blood flows through a section of a horizontal artery that is partially blocked by a deposit along the artery wall. A hemoglobin molecule moves from the narrow region into the wider region. What happens to the pressure acting on the molecule as it moves from the narrow to the wider region?

the pressure increases

The speed of sound waves having a frequency of 256 Hz compared to the speed of a sound wave having a frequency of 512 Hz is

the same

Two objects with different masses collide with and stick to each other. Compared to before the collision, the system of two objects after the collision has

the same amount of total momentum but less total kinetic energy.

A beaker is filled with water to the rim. Gently you place a toy duck in the beaker and some of the water spills out. The duck floats. The weight of the beaker with the duck floating in it is

the same as its weight before adding the duck.

Suppose you have an aquarium. You have a solid plastic decoration and a rock of about the same volume but the rock has twice the mass. Both are totally submerged in the water. The buoyant force on the plastic object is about

the same as that on the rock.

A sinusoidal force with a given amplitude is applied to an oscillator. To maintain the largest amplitude oscillation, the frequency of the applied force should be

the same as the natural frequency of the oscillator.

Compared to a gear tooth on the rear sprocket (on the left, of small radius) of a bicycle, a gear tooth on the front sprocket (on the right, of large radius) has

the same linear speed and a slower angular speed.

a small car mashes with a large truck in a head on collision. Which of the following statements concerning the magnitude of the average force during the collision correct?

the small car and the truck experience the same average force

You wish to increase the temperature of a 1.00-kg block of a certain solid substance from 20°C to 25°C. (The block remains solid as its temperature increases.) To calculate the amount of heat required to do this, you need to know

the specific heat of the substance.

When blood flows into an aneurysm

the speed decreases and the pressure increases.

A pitcher contains 0.50 kg of liquid water and 0.50 kg of ice at 0°C. You let heat flow into the pitcher until there is 0.75 kg of liquid water and 0.25 kg of ice. During this process

the temperature of the ice-water mixture remains the same.

An elevator is being lifted up an elevator shaft at a constant speed by a steel cable as shown in the figure above. All frictional effects are negligible. In this situation, forces on the elevator are such that

the upward force by the cable is equal to the downward force of gravity.

A ball sits at rest on a horizontal tabletop. According to Newton's third law, by itself (F A on B = -F B on A), the weight of the ball has the same magnitude as

the upward force that the ball exerts on planet earth.

A yo-yo is placed on a horizontal surface as shown. There is sufficient friction for the yo-yo to roll without slipping. If the string is pulled to the right as shown with a force of constant magnitude F,

the yo-yo rolls to the right.

During a brown-out, the electric power company drops the voltage of the power line and the incandescent light bulbs in your house become dimmer. When this happens, the filaments in the bulbs operate at a lower than normal temperature, so

their color is somewhat redder than normal

How many nodes and antinodes are shown in the standing wave below?

three nodes and two antinodes

You are riding an amusement park ride where you are strapped to the inside of a giant metal wheel. During some time interval the wheel is horizontal and rotating uniformly and rapidly. During this time interval your acceleration is

towards the center of the wheel.

If only conservative forces act on a system, the total mechanical energy of the system remains constant.

true

is it possible for heat to flow across a vacuum

true

A roller coaster car moves around a vertical circle. At the bottom of the circle, the car experiences four times as much radial acceleration as at the top of the circle. Compared to its at the top of the circle, the speed of the car at the bottom circle is

twice as great

You drive a race car around a circular track of radius 100 mat a constant speed of 100 km/h. If you then drive the same car around a different circular track of radius 200 m at a constant speed of 200 km/h, your acceleration will be

twice as great.

If you double the wavelength of a wave on a string, what happens to the wave speed v and the wave frequency f ?

v is unchanged and f is doubled.

A traffic light of weight w hangs from two lightweight cables as shown. Each cable hangs at a angle from the vertical. What is the tension in each cable?

w/ sqrt2

Which has the higher specific heat, water or land?

water

Two carts A and B are moving towards each other as shown in the diagram. They collide and come to rest at the point of impact. From this observation we can conclude that the carts

were moving with momenta equal in magnitude and opposite in direction.

The force on a damped oscillator is Fx = -kx - bvx. During its motion, the oscillator loses mechanical energy most rapidly

when it is at either maximum positive or maximum negative displacement.

A woman exerts a constant horizontal force on a large box. As a result, the box moves across a horizontal floor at a constant speed v0. If the woman doubles the constant horizontal force that she exerts on the box, and the force resisting the motion of the box does not change, the box then moves

with constantly increasing speed

Two blocks are connected as shown. When released, the 6.00-kg block accelerates downward and the 8.00-kg block accelerates to the right. After each block has moved 2.00 cm, the force of gravity has done

work on the 6.00-kg block only.

Is it possible to have motion in the absence of a net force?

yes

Three blocks are connected as shown. The ropes and pulleys are of negligible mass. When released, block C moves downward, block B moves up the ramp, and block A moves to the right. After each block has moved a distance d, the force of gravity has done

zero work on A, negative work on B, and positive work on C.