Physics Cumulative Exam
Which of the following equations can be used to directly calculate the change in an object's momentum?
Dp = FDt
A row of six 1.0 N wooden blocks is being pushed across a tabletop at a constant speed by a toy tractor that exerts a force of 1.3 N on the row. What is the coefficient of kinetic friction between the wooden blocks and the tabletop?
0.22
A net force of 6.8 N accelerates a 31 kg scooter across a level parking lot. What is the magnitude of the scooter's acceleration?
0.22 m/s^2
A hiker wears a 7.5-kg backpack while climbing a mountain. After 30.0 min, the hiker is 8.2 m above the starting point. What is the average amount of power created by the hiker?
0.34 W
A car has four tires that are each inflated to an absolute pressure of 2.0 x 10^5 Pa. Each tire has an area of 0.024 m^2 in contact with the ground. How much does the car weigh?
1.9 x 10^4 N
Which equation expresses the conservation of mechanical energy in a system where the only forms of mechanical energy are kinetic energy and elastic potential energy?
1/2mvi2 + 1/2kxi2 = 1/2mvf2 + 1/2kxf2
Which equation expresses the conservation of mechanical energy in a system that involves kinetic energy, gravitational potential energy, and elastic potential energy?
1/2mvi2 + mghi + 1/2kxi2 = 1/2mvf2 + mghf + 1/2kxf2
An ideal fluid flows through a pipe made of two sections with diameters of 1 cm and 3 cm, respectively. By what factor would you have to multiply the velocity of the liquid flowing through the 1 cm section to obtain the velocity of liquid flowing through the 3 cm section?
1/9
To melt 4 kg of a solid, 10^6 J of heat is required. Which of the following expressions gives the heat of fusion of the solid?
10^6/4 J/kg
A child rides a bicycle in a circular path with a radius of 2.0 m. The tangential speed of the bicycle is 2.0 m/s. The combined mass of the bicycle and the child is 43 kg.
2.0 m/s^2
A 35 kg child moves with uniform circular motion while riding a horse on a carousel. The horse is 3.2 m from the carousel's axis of rotation and has a tangential speed of 2.6 m/s.
2.1 m/s^2
Two perpendicular forces, one of 45.0 N directed upward and the other of 60.0 N directed to the right, act simultaneously on an object with a mass of 35.0 kg. What is the magnitude of the resultant acceleration of the object?
2.14 m/s^2
A piano that weighs 575 N is lifted 20.0 m straight up by a rope attached to a motor-driven winch. It takes 10.0 s for the piano to reach this height. What power is developed by the motor in kW?
2.25 kW
A car on a roller coaster loaded with passengers has a mass of 2.0 ´ 10^3 kg. At the lowest point of the track, the radius of curvature of the track is 24 m and the roller car has a tangential speed of 17 m/s.
2.4 x 10^4 N
A 5.0 kg hoop rotates about a perpendicular axis through its center. A force of 25 N is exerted tangentially to the hoop. If the hoop has a radius is 2.0 m, what is its angular acceleration?
2.5 rad/s^2
Each of four tires on an automobile has an area of 0.026 m^2 in contact with the ground. The weight of the automobile is 2.6´10^4 N. What is the pressure in the tires?
2.5 x 10^5 Pa
A faucet tap with a diameter of 2.0 cm fills a 2.5 x 10^-2 m^3 container in 30.0 s. What is the speed of the water flow?
2.7 m/s
A water bed weighs 1025 N, and is 1.5 m wide by 2.5 m long. How much pressure does the water bed exert if the entire lower surface of the bed makes contact with the floor?
2.7 x 10^2 Pa
A washing machine has a fast spin cycle of 542 rev/min and a slow spin cycle of 328 rev/min. The diameter of the washing machine drum is 0.43 m. What is the ratio of the centripetal accelerations for the spin cycles?
2.73
A girl pushes a box that has a weight of 450 N up an incline. If the girl exerts a force of 150 N along the incline, what is the mechanical advantage of the incline?
3.0
If the air pressure in a tire is measured as 2.0´10^5 Pa, and atmospheric pressure equals 1.0´10^5 Pa, what is the absolute pressure of the air inside the tires?
3.0x10^5 Pa
What is one kilowatt-hour equivalent to?
3.6 x 10^6 Joules
A 1.0 m-long lever is attached to a rotating rod that is perpendicular to the lever. By pushing down on the end of the lever with a force of 60 N, you can rotate the rod. If the force on the lever is exerted at a 30º angle, what torque is exerted on the lever? (sin 30º = 0.5; cos 30º = 0.87, tan 30º = 0.58)
30 N•m
What is the efficiency of a machine that requires 1.00´10^2 J of input energy to do 35 J of work?
35%
Sam must perform a job that requires a torque of 32.4 N·m. He must use a 0.234-m-long wrench and exert a force of 232 N. What is the smallest angle, with respect to the vertical, that Sam needs to exert this amount of force?
36.6º
How much power is required to lift a 2.0 kg mass at a speed of 2.0 m/s?
39 W
The gravitational force between two masses is 36 N. What is the gravitational force if the distance between them is tripled? (G = 6.673´10^-11 N·m^2/kg^2)
4.0 N
There are six books in a stack, and each book weighs 5 N. The coefficient of static friction between the books is 0.2. With what horizontal force must one push to start sliding the top five books off the bottom one?
5 N
50 g of ice at 0°C is dropped in a beaker containing 100 g of water at 0°C. What will be the contents of the beaker after 5 hours? Assume that the room temperature is 0°C.
50 g of ice and 100 g of water
A cube of wood with a density of 0.780 g/cm^3 is 10.0 cm on each side. When the cube is placed in water, what buoyant force acts on the wood? (rw = 1.00 g/cm^3)
7.65 N
A late traveler rushes to catch a plane, pulling a suitcase with a force directed 30.0° above the horizontal. If the horizontal component of the force on the suitcase is 60.6 N, what is the force exerted on the handle?
70.0 N
A child rides a bicycle in a circular path with a radius of 2.0 m. The tangential speed of the bicycle is 2.0 m/s. The combined mass of the bicycle and the child is 43 kg.
86 N
A solid wooden wheel accelerates at 3.25 rad/s^2 when a force of 4.5 N exerts a torque on it. If this wheel is replaced by a wheel with all of its mass on the rim, the moment of inertia is given by I = mr2. If the same angular velocity were desired, what force would have to be exerted on the wheel?
9.0 N
A planet has a mass of about 6.4 x 10^23 kg, and its moon has a mass of about 9.6 x 10^15 kg. If the magnitude of the gravitational force between the two bodies is 4.6 x 10^15 N, how far apart are the planet and its moon
9.4 X 10^6
A sled weighing 1.0 ´ 10656-05-04-00-00_files/i0050000.jpg N is held in place on a frictionless 20.0° slope by a rope attached to a stake at the top. The rope is parallel to the slope. What is the normal force of the slope acting on the sled?
94 N
Joe is standing on the pedal of a bicycle. If his mass of 65 kg, the pedal makes an angle of 55º above the horizontal, and the pedal is 18 cm from the center of the chain ring, how much torque does he exert?
94 N·m
Which situation shows unbalanced forces acting on an object?
A book sitting still and then sliding on a table top.
In which of the following scenarios is work done?
A car applies the breaks and decelerates while traveling on a flat stretch of road.
In which of the following scenarios is no net work done?
A car travels at constant speed on a flat road.
Which of the following statements is not correct?
A fluid has a definite shape.
Which of the following statements properly relates the variables in the equation FDt = Dp?
A large constant force acting over a long time interval causes a large change in momentum.
How does a liquid differ from a gas?
A liquid has definite volume, unlike a gas.
If a force is exerted on an object, which statement is true?
A small force applied over a long period of time can produce a large change in the objects momentum.
Which of the following situations is an example of a significant change in momentum?
A tennis ball is hit into a net.
Which of the following is a correct interpretation of the expression ag = g = G(mE/r^2)
All of the above are correct interpretations.
What description explains the situation where an elephant and a feather are falling from a high building?
All of the above.
Which situation illustrates Newton's first law?
All of the above.
If you are able to see an object, how can you be sure that it is not at absolute zero?
As soon as light hits the object, it gives the object energy and it will no longer be at absolute zero
___________ is a force which is applied to an object by another object or a person. __________ is a force that always opposes the motion of an object and is frequently ignored.
Applied force, air resistance
A hard drive on a modern computer spins at 7200 rpm (revolutions per minute). If the drive is designed to start from rest and reach operating speed in 1.5 s, then the angular acceleration of the disk must be 2.0 x 10^3 rad/s^2.
F
According to the First Law of Thermodynamics, the change in thermal energy of an object is equal to the heat added to the object divided by the work done by the object.
F
If a planet has twice the mass of Earth, its radius would have to be larger by a factor of 2 for the gravitational field strength at the planet's surface to be the same as on Earth's surface.
F
In a gas kept at a constant temperature, all molecules move with the same speed.
F
Jack and Joe carry a surfboard that is 2.43 m long and weighs 143 N. Jack lifts one end with a force of 57 N. Joe must exert a force of 22 N.
F
Mass is the magnitude of the force due to gravity acting on an object.
F
Newton's Second Law for rotational motion states that angular acceleration is directly proportional to net torque and the moment of inertia.
F
You replace the tires on your car with tires that have a larger diameter. After you change the tires, for trips at the same speed and over the same distance, the angular velocity and number of revolutions will both increase.
F
What is true of the velocity versus time graph of an object receiving an applied net force?
It will be a line with either a positive or a negative slope.
How would the speed of Earth's orbit around the sun change if Earth's distance from the sun increased by 4 times?
It would decrease by a factor of 2.
Which of the following are not units of power?
J
Which of the following units are not used to measure temperature?
Joule
Which planets have the largest accelerations of gravity?
Jupiter, Neptune, Saturn
Which of the following formulas would be used to directly calculate the kinetic energy of an object with mass m bouncing up and down on a spring with spring constant k?
KE = 1/2mv^2
Which of the following is a direct cause of a substance's temperature increase?
Kinetic energy is added to the particles of the substance.
Why doesn't the principle of mechanical energy conservation hold in situations when frictional forces are present?
Kinetic energy is not completely converted to a form of potential energy.
Which of the following is not a valid equation for mechanical advantage?
MA = Wout/Win
Which equation expresses the conservation of mechanical energy using only the basic term for mechanical energy?
MEi = MEf
Which of the following statements about the conservation of momentum is not correct?
Momentum is not conserved for a system of objects in a head-on collision.
What is the common formula for work? Assume that W is the work, F is a constant force, -v is the change in velocity, and d is the displacement.
W = Fd
Which of the following equations expresses the work-kinetic energy theorem?
Wnet = KE
Which forces can do work on an object?
a and c are correct.
Gravitational potential energy is always measured in relation to
a zero level.
The angular displacement of an object divided by the time needed to make the displacement.
angualr velocity
If you want to open a swinging door with the least amount of force, where should you push on the door?
as far from the hinges as possible
Imagine a figure skater performing a spin. What will happen to angular velocity as the skater's leg is extended?
decrease
In an ____ collision, total system kinetic energy is conserved, but in an __________ collision, total system kinetic
elastic, inelastic
What causes a moving object to change direction?
force
Which of the following is the cause of an acceleration?
force
A child rides a bicycle in a circular path with a radius of 2.0 m. The tangential speed of the bicycle is 2.0 m/s. The combined mass of the bicycle and the child is 43 kg.
friction
What causes a pulley system to be inefficient?
friction
Which form of energy is involved in weighing fruit on a spring scale?
gravitational potential energy and elastic potential energy
In the figure above, according to Kepler's laws of planetary motion,
if Dt1 = Dt2, then A1 = A2
The centripetal force on an object in circular motion is
in the plane of the object's motion and perpendicular to the tangential speed.
When a car makes a sharp left turn, what causes the passengers to move toward the right side of the car?
inertia
Which of the following is the tendency of an object to maintain its state of motion?
inertia
An object's tendency to resist acceleration is measured by the object's
inertial mass.
When an object is moving with uniform circular motion, the object's tangential speed
is constant.
A force does work on an object if a component of the force
is parallel to the displacement of the object.
What happens to the internal energy of an ideal gas when it is heated from 0°C to 4°C?
it increases.
A newton is equivalent to which of the following quantities?
kg x m/s^2
Which of the following is not an example of units for expressing pressure?
kg/m^2
Which of the following energy forms is associated with an object in motion?
kinetic energy
The main difference between kinetic energy and potential energy is that
kinetic energy involves motion, and potential energy involves position.
The length of a force vector represents the
magnitude of the force
Which of the following energy forms is associated with an object due to its position?
potential energy
Which of the following is the rate at which energy is transferred?
power
Which of the following is the rate at which work is done?
power
For incompressible fluids, density changes little with changes in
pressure.
The free-body diagram shown above represents a car being pulled backwards by a towing cable. In the diagram, the 5800 N force is
the force exerted by the towing cable on the car.
What is true about the forces that act on a book that slides across a table and comes to a stop?
the force of friction changes the state of motion of the book
What does the difference between gauge pressure and absolute pressure equal?
the pressure at the surface of the fluid
The law of conservation of momentum states that
the total momentum of all objects interacting with one another remains constant regardless of the nature of the forces between the objects.
As an object falls toward Earth,
the upward acceleration of Earth is negligible because of its large mass.
Two swimmers relax close together on air mattresses in a pool. One swimmer's mass is 48 kg, and the other's mass is 55 kg. If the swimmers push away from each other,
their momenta are equal but opposite.
Which of the following quantities measures the ability of a force to rotate or accelerate an object around an axis?
torque
Which of the following is a true statement about the conservation of energy?
total energy is always conserved.
Which of the following properties is not characteristic of an ideal fluid?
turbulent flow
An __________ force must act on an object in order for it to move in a circle. This fact is described by Newton's _____ Law.
unbalanced, first
Which of the following physical properties can be used to measure temperature using a thermometer?
volume
Earth has a mass of 5.97 x 10^24kg, and a mean radius of 6.38 x 10^6m. What would be the orbital speed and period of a satellite in orbit 1.44 x 10^8 m above Earth?
vt = 1630 m/s T = 5.78x10^5 s
A person sitting in a chair with wheels stands up, causing the chair to roll backward across the floor. The momentum of the chair
was zero while stationary and increased when the person stood
A change in the gravitational force acting on an object will affect the object's
weight.
A car goes forward along a level road at constant velocity. The additional force needed to bring the car into equilibrium is
zero.
In general, Fnet equals
ΣF.
A 1.80 m ladder rests on two supports. Support A is 0.60 m from one end of the ladder, while support B is 0.15 m from the other end of the ladder. Which of the following statements about the forces acting on the ladder is true?
Support A exerts a greater force.
A liquid has a definite volume but not a definite shape.
T
A stunt driver maneuvers a sportscar so that it is traveling on only two wheels. The center of mass of the car is directly above the line between the points where the two wheels are touching the ground.
T
According to the Second Law of Thermodynamics, natural processes go in a direction that increases the total entropy in the universe.
T
Density determines whether an object sinks or floats.
T
Kepler's third law of planetary motion states that the square of a planet's orbital period is proportional to the cube of the average distance between the planet and the sun.
T
Only the mass of the planet and radius of the orbit are needed to calculate the orbital speed of a satellite.
T
The center of mass of a car tire is in the middle of the tire.
T
The entropy of a system measures the state of disorder of the system.
T
The entropy of an isolated system never decreases.
T
The equation for centripetal force can be derived by substituting the equation for centripetal acceleration into Newton's second law.
T
The equation for the conservation of momentum in a two-body system is m1v1,i + m2v2,i = m1v1,f + m2v2,f.
T
The temperature of a bottle containing water rises when it is shaken vigorously since shaking adds heat to the system
T
The temperature of a gas is related to the kinetic energy of the particles in the gas.
T
Which statement about the acceleration of an object is correct?
The acceleration of an object is directly proportional to the net external force acting on the object and inversely proportional to the mass of the object.
Which of the following statements about completely submerged objects resting on the ocean bottom is correct?
The apparent weight of the object depends on the object's density.
A wooden beam that is 6.50 m long weighs 325 N. It rests on two supports that are 3.00 m apart, with equal amounts of the beam extending from each end. Sarah, who weighs 575 N, stands on the beam in the center and then walks toward one end. What will happen to the beam as Sarah moves toward the end?
The beam will tip over and fall as equilibrium is disrupted.
When a closed tin is heated, the pressure inside it increases. This happens because:
The molecules move faster and each molecule strikes the walls of the tin more often.
How many action-reaction force pairs are involved when two people pull on opposite ends of a rope?
There are more than three.
What feature of double-glazed windows makes them good insulators?
There is a vacuum between the panes of glass
A truck travels 420 m. Each tire on the truck has a diameter of 42 cm. If one revolution of a tire is equal to 2π times the radius of the tire (in meters), which of the following equations shows how many revolutions each tire makes as the distance is traveled?
(1.0x10^3)/(pi) rev
What is the angular displacement of the second hand on a clock after 59 seconds?
-6.17 rad
The drum of a clothes dryer turns at 635 rev/min. If the door to the dryer is opened, the motor is turned off. If the drum requires 8.0 s to slow to a stop, what is the angular acceleration of the drum?
-8.3 rad/s^2
A single force acts on an object. The components of this force act along the +x-axis and the -y-axis. The single force that will bring the object into equilibrium has components that act along the
-x-axis and +y-axis.
If the mass in a horizontal mass-spring system was doubled, the elastic potential energy in the system would change by a factor of
0 (no change).
A worker does 25 J of work lifting a bucket, then sets the bucket back down in the same place. What is the total net work done on the bucket?
0 J
A 0.105-kg soccer ball moving at 24 m/s is caught and held by a 75-kg goalie at rest. With what speed does the goalie fly backward?
0.034 m/s
A 45.0 kg ice skater needs a 25 N horizontal force to get moving on a smooth ice surface. What is the coefficient of friction between the ice and the skates?
0.057
A toy consists of a .46m rod with negligible weight and a 0.45 kg ball at one end. Find the moment of inertia of the toy. The moment of inertia is to be found about the far end of the rod.
0.095 kg·m^2
What torque must be applied to a wheel with a moment of inertia of 0.19 kg·m^2 to make it rotate at 11 rad/s in 10 s?
0.21 Nm
A waitperson carrying a tray with a platter on it tips the tray at an angle of 12° below the horizontal. If the gravitational force on the platter is 5.0 N, what is the magnitude of the force parallel to the tray that tends to cause the platter to slide down the tray? (Disregard friction.)
1.0 N
Two boxes are placed at opposite ends of a 3.0 m long board. The board is supported underneath by a fulcrum. The box on the left has a mass of 25kg, and the box on the right has a mass of 15 kg. Ignoring the mass of the board, where should the fulcrum be positioned under the board in order to balance the masses horizontally?
1.1 m from the left
A truck's specifications state that its weight distribution is 53% on the front tires and 47 percent on the rear tires. Its wheel base is 2.46 m. How far from the front tires is the truck's center of mass located?
1.16 m
A person drives to the top of a mountain. On the way up, the person's ears fail to "pop," or equalize the pressure of the inner ear with the outside atmosphere. The pressure of the atmosphere drops from 1.010 x 10^5 Pa at the bottom of the mountain to 0.998 x 10^5 Pa at the top. Each eardrum has a radius of 0.40 cm. What is the pressure difference between the inner and outer ear at the top of the mountain?
1.2 x 10^3 Pa
Carrie has a mass of 43 kg and sits 1.8 m from the center of a seesaw. Steve wants to balance Carrie. If Steve has a mass of 52 kg, how far from the center of the seesaw should he sit?
1.5 m
A diver with a mass of 80.0 kg jumps from a dock into a 130.0 kg boat at rest on the west side of the dock. If the velocity of the diver in the air is 4.10 m/s to the west, what is the final velocity of the diver after landing in the boat?
1.56 m/s to the west
What is the temperature of a system in thermal equilibrium with another system made up of water and steam at 1 atm of pressure?
100 °C
What is the kinetic energy of a 0.135 kg baseball thrown at 40.0 m/s?
108 J
The free-body diagram shown above represents a car being pulled by a towing cable. In the diagram, which of the following is the gravitational force acting on the car?
14 700 N
An iron bar is used to lift a slab of cement. The force applied to lift the slab is 4.0 ´ 10656-09-04-00-00_files/i0120000.jpg N. If the slab weighs 6400 N, what is the mechanical advantage of the bar?
16
Water has a pressure of 3.00 x 10^5 Pa and a speed of 1.00 m/s as it flows through a horizontal pipe. At a certain point, the pipe narrows to one-fourth its original diameter. (Remember the radius is half of the diameter, so its radius will also be one-fourth its original size.) What is the speed of the water flow in the narrow section of the pipe?
16.0 m/s
A waitperson pushes the bottom of a glass tumbler full of water across a tabletop at constant speed. The tumbler and its contents have a mass of 0.70 kg, and the coefficient of kinetic friction for the surfaces in contact is 0.41. What force does the waitperson exert on the glass? g = 9.81 m/s^2)
2.8 N
A horizontal force of 200 N is applied to move a 55 kg television set across a 10 m level surface. What is the work done by the 200 N force on the television set?
2000 J
A heavy bank-vault door is opened by the application of a force of 3.0´10^2 N directed perpendicular to the plane of the door at a distance of 0.80 m from the hinges. What is the torque?
240 Nm
A construction worker pushes a wheelbarrow 5.0 m with a horizontal force of 50.0 N. How much work is done by the worker on the wheelbarrow?
250 J
The mass of ball B is 1 kilogram and its speed is 1 m/sec. The mass and the speed of ball A is three times the mass and the speed of ball B. What is the ratio of the kinetic energy of ball A to ball B? Hint: Divide the kinetic energy equation for ball A by the kinetic energy equation of ball B.
27
A water tunnel has a circular cross section where the diameter diminishes from 3.6 m to 1.2 m. If the velocity of water is 3.0 m/s in the larger part of the tunnel, what is the velocity of water in the smaller part of the tunnel?
27 m/s
A water bed that is 1.5 m wide and 2.5 m long weighs 1055 N. Assuming the entire lower surface of the bed is in contact with the floor, what is the pressure the bed exerts on the floor?
280 Pa
A 3.00 kg toy falls from a height of 1.00 m. What will the kinetic energy of the toy be just before the toy hits the ground? (Assume no air resistance and that g = 9.81 m/s^2)
29.4 J
Two small masses that are 10.0 cm apart attract each other with a force of 10.0 N. When they are 5.0 cm apart, these masses will attract each other with what force?
40.0 N
In the free-body diagram shown above, which of the following is the gravitational force acting on the balloon?
4050 N
A planet has a mass of 5.97 x 10^24 kg and a radius of 6.38 x 10^6 m. Find the weight of a 65.0 kg person at 1000 km above the surface of this planet.
475 N
A gear spins at 1880 rev/min. What is the angular displacement of the gear in 2.50s?
492 rad
What is the average power supplied by a 60.0 kg person running up a flight of stairs a vertical distance of 4.0 m in 4.2 s?
560 W
If the flow rate of a liquid is measured at 8.0 ´ 10^3 m^3/s going through a 20.0 m radius pipe, which of the following is the average fluid velocity in the pipe?
6.4 m/s
A 20.0 kg block of ice is sitting in a cooler. The temperature of the ice is 0.0ºC when it is put into the cooler. As it melts, how much heat does the block of ice absorb?
6.68 x 10^6 J
What is true about mechanical energy?
An object with mechanical energy can exert an applied force on another object.
What is true about satellites?
Both a and b.
Which of the following choices correctly describes the orbital relationship between Earth and the sun?
Earth orbits the sun in an ellipse, with the sun at one focus
Two people are holding up the ends of a 4.25-kg wooden plank. A 6.00-kg box sits in the center of the plank. What forces do the people exert on the plank? Hint: The forces of the people must equal the forces acting on the box and the plank.
Fright = 50.5 N, Fleft = 50.5 N
Convection occurs in what states of matter?
Gases and Liquids
Which of the following is true about how pressure varies with depth in a fluid?
Pressure increases with depth because it must support the fluid weight above it.
Which of the following statements is true according to Pascal's principle?
Pressure in a fluid is the same throughout the fluid.
For an ideal fluid flowing through a horizontal pipe, Bernoulli's principle and the continuity equation state that the pressure within the pipe does which of the following? (Assume measurements are taken along the pipe in the direction of fluid flow.)
Pressure increases as the pipe diameter increases.
A _____________ is used to describe a fraction of a revolution.
Radian
In which of the following sentences is work used in the scientific sense of the word?
Sam and Rachel pushed hard, but they could do no work on the car.
In which of the following sentences is work used in the everyday sense of the word?
Sam and Rachel worked hard pushing the car.
A child with a mass of 23 kg rides a bike with a mass of 5.5 kg at a velocity of 4.5 m/s to the south. Compare the momentum of the child with the momentum of the bike.
The child has a greater momentum than the bike.
What are the units of the coefficient of friction?
The coefficient of friction has no units
If an object is only partially submerged in a fluid, which of the following is true?
The density of the fluid is greater than the density of the object.
Why isn't there a change in temperature during a phase change?
The energy would be used by the increasing motion of molecules
A 4.5-m-long wooden board with a 24-kg mass is supported in two places. One support is directly under the center of the board, and the other is at one end. What can be said about the forces exerted by the supports?
The force exerted by the center support is greater than the force exerted by the end support.
Which action-reaction force pair is correct for a car moving along a road?
The force of the wheels on the road and the force of the road on the wheels.
When a gas is transferred from one container into another container, which of the following does not occur?
The gas keeps its original volume.
Why does an astronaut weigh less on the moon than on Earth?
The gravitational field strength is less on the moon's surface than on Earth's surface.
When comparing the momentum of two moving objects, which of the following is correct?
The less massive object will have less momentum if the velocities are the same
What conditions must be met for an object to be at equilibrium?
The net force and net torque must both equal zero.
What happens to the pressure within a fluid as its velocity increases?
The pressure within the fluid decreases.
What is a power rating?
The rate at which a machine can do work upon other objects.
How would the speed of Earth's orbit around the sun change if Earth's mass increased by 4 times?
The speed would not change.
A hockey stick hits a puck on the ice. Identify an action-reaction pair in this situation.
The stick exerts a force on the puck; the puck exerts a force on the stick.
A ladder is placed on two supports. What condition must be met if both supports need to exert the same force on the ladder while keeping it in equilibrium?
The supports should be equal distances from the center of mass.
A free-body diagram of a ball falling in the presence of air resistance would show
a downward arrow to represent the force due to gravity and an upward arrow to represent the force of air resistance.
What kind of simple machine are you using if you pry a nail from a board with the back of a hammer?
a lever
Which of the following is not an example of turbulent flow?
a river flowing slowly in a straight line
If a nonzero net force is acting on an object, then the object is definitely
being accelerated.
What characteristics does a powerful lineman on a football team have?
can apply a large force and has a large velocity
Newton's law of universal gravitation
can be used to derive Kepler's third law of planetary motion.
A pendulum is raised 1.5 cm and allowed to fall. If air resistance is negligible, how high will the pendulum rise on the other side?
exactly 1.5 cm
Where should a force be applied on a lever arm to produce the most torque?
farthest from the axis of rotation
What is a force that does not involve physical contact between two objects?
field force
Which of the following is a fluid?
helium
A measure of the quantity of matter is
mass.
Which of the following refers to the sum of kinetic energy and all forms of potential energy?
mechanical energy
In a two-body collision,
momentum is always conserved.
The impulse experienced by a body is equivalent to the body's change in
momentum.
A crate is released on a frictionless plank inclined at angle q with respect to the horizontal. Which of the following relationships is true? (Assume that the x-axis is parallel to the surface of the incline.)
none of the above
In the presence of frictional force,
nonmechanical energy is no longer negligible and mechanical energy is no longer conserved.
Which of the following equations can be used to directly calculate an object's momentum, p?
p = mv
A rubber ball moving at a speed of 5 m/s hit a flat wall and returned to the thrower at 5 m/s. The magnitude of the momentum of the rubber ball
remained the same.
A soccer ball collides with another soccer ball at rest. The total momentum of the balls
remains constant.
Which of the following is not an example of laminar flow?
smoke twisting as it moves upward from a fire
If you lift an apple from the ground to some point above the ground, the gravitational potential energy in the system increases. This potential energy is stored in
the gravitational field between Earth and the apple.
Two objects with different masses collide and bounce back after an elastic collision. Before the collision, the two objects were moving at velocities equal in magnitude but opposite in direction. After the collision,
the less massive object had gained momentum.
According to Newton's second law, when the same force is applied to two objects of different masses,
the object with greater mass will experience a smaller acceleration, and the object with less mass will experience a greater acceleration.