Unit 4 AP Physics mcq, Unit3 AP Physics mcq, Unit 2 AP Physics mcq, Unit 1 AP Physics MCQ

An object starts at rest and moves in a horizontal circle such that its tangential speed increases linearly as a function of time. Which of the following graphs shows how the centripetal acceleration behaves as a function of time?

) ) ) curved up and right concave up

A student places a block on a disk, and the edge of the disk makes one revolution in a constant time interval △t▵t. A force probe is attached to the block and the center of the disk, as shown above. In an experiment, a student measures the centripetal force exerted on the block when placed at various distances from the center of the disc while the tangential speed of the edge of the disc remains constant. Which of the following graphs shows the centripetal force exerted on the block as a function of its distance from the center of the disk?

/ / / /

A block of mass 3kg3kg on a horizontal surface travels at 6m/s6m/s toward the free end of a horizontal spring of negligible mass and spring constant k=200N/mk=200N/m , as shown in the figure. The other end of the spring is attached to a wall, and there is negligible friction between the block and the horizontal surface. The block comes into contact with the free end of the spring such that the block remains fixed to the spring as the spring is compressed. A graph of the kinetic energy of the block as a function of the distance the spring is compressed is shown that was collected from experimental data. Which of the following data tables could best represent the spring potential energy of the block-spring system as a function of the distance that the spring is compressed?

0 0 .3 9 .6 36

One end of a vertical spring is attached to the ground with the other end above the ground such that the spring is at its equilibrium position. The spring has negligible mass and a spring constant k0k0 , as shown in Figure 1. When an object of mass m0m0 is released from rest above the spring, the object falls and then makes contact with the top of the spring with a speed v0v0 , as shown in Figure 2. The spring then compresses such that the object reaches a position x0x0 below the spring's equilibrium position, as shown in Figure 3, where the object comes to rest. The object is then directed upward by the spring until it is no longer in contact with the spring. The object then continues upward. The object-spring-Earth system has zero gravitational potential energy at the instant shown in Figure 2. All frictional forces are considered to be negligible. When the object is located at the position shown in Figure 3, which of the following equations correctly indicates the total mechanical energy of the object-spring-Earth system?

1/2kx^2-mgx

A car travels with a tangential speed v1v1 around a curve of radius rr and turns to the left, as shown by the rear view of the car in Figure 1. A force diagram of the forces exerted on the car with speed of 5m/s5⁢m/s as it turns is shown in Figure 2. A force diagram of the forces exerted on the car with speed vv as it turns around the same curve of the same radius is shown in Figure 3. The speed vv of the car in figure 3 is most nearly

15m/s

A moon orbits a planet in a nearly circular orbit of radius RR, as shown in the figure. The moon has a mass of 1×1022 kg1×1022 kg, and the gravitational field strength at a distance RR from the planet is 0.001 N/kg0.001 N/kg. What is the gravitational force exerted on the moon while it is in orbit around the planet?

1×10^19 N

At time t=0st=0⁢s, object XX of mass MM travels at a constant speed of 2 m/s2 m/s to the right toward object YY of mass 2M2M that is a distance of 8m8m away from object XX while at rest, as shown above. Both objects are on a horizontal surface, where the frictional forces may be considered negligible. Which of the following pairs of force diagrams represents the forces exerted on object XX and object YY at t=4 st=4 s?

2 spaces out to each side same size for each horizontal vector

A 5 kg5 kg block moves with a constant speed of 10 ms10 ms to the right on a smooth surface where frictional forces are considered to be negligible. It passes through a 2.0 m2.0 m rough section of the surface where friction is not negligible, and the coefficient of kinetic friction between the block and the rough section μkμ⁢k is 0.2. What is the change in the kinetic energy of the block as it passes through the rough section?

20 J of energy is removed from the block.

Block AA is placed on a rough surface inclined at an angle θθ above the horizontal. A taut string connects block AA over a pulley to block BB, which hangs from the string, as shown below. The masses of blocks AA and BB are MAMA and MBMB, respectively. At time t=0t=0, block AA is sliding up the slope as block BB falls, and the blocks are both slowing down. Assume that the mass and friction of the pulley are negligible. If the mass of block BB is 2kg2kg, the gravitational force exerted on block BB is most nearly which of the following?

20N

A moon of mass 1×1020 kg1×1020 kg is in a circular orbit around a planet. The planet exerts a gravitational force of 2×1021 N2×1021 N on the moon. The centripetal acceleration of the moon is most nearly

20m/s^2

Two containers of water can have their individual masses varied by adding or removing water. The containers are initially a distance dd apart, as measured from their centers, and are filled with water so that each has a mass MM, as shown in Figure 1 above. The gravitational force that one container exerts on the other is F0F0. Water is then added to one container so that its mass increases to 1.5M1.5M, and water is removed from the other container so that its mass decreases to 0.5M0.5M, as shown in Figure 2. What is the new gravitational force exerted on one container by the other?

3/4 Fo

At one point in their individual orbits, three planets, X,Y,& ZX,Y,& Z, are along the same horizontal line. The gravitational force on Planet XX from Planet ZZ is F0F0. The distance from the center of mass of each planet to an adjacent planet is given in terms of R0R0, and their respective masses are given in terms of M0M0, as shown above. What is the net force on Planet YY, and what reasoning supports this claim?

5F0 to the right, because the gravitational force from Planet YY is greater than the gravitational force from Planet XX.

A 5kg5⁢kg object is released from rest near the surface of a planet such that its gravitational field is considered to be constant. The mass of the planet is unknown. After 2s2⁢s, the object has fallen 30m30m. Air resistance is considered to be negligible. What is the gravitational force exerted on the 5kg5⁢kg object near the planet's surface?

75N

A 2 kg2 kg object is released from rest near the surface of a planet with a negligible atmosphere. A graph of the object's speed vv as a function of time tt is shown. What is the weight of the object on the planet?

8N

A scientist designs an experiment that requires two atomic particles whose only fundamental force exerted between them is the gravitational force. Which combination of particles and separation distance will meet this condition?

A proton and neutron located 1.0 mm apart

In which of the following situations is the gravitational force the dominant force? Select two answers.

A satellite is in orbit around a planet. An object is in free fall just after it is released from rest.

A block of mass MM on an inclined surface is attached to a spring of negligible mass, as shown. The other end of the spring is attached to a wall, and there is negligible friction between the block and the incline. The block is pulled to a position such that the spring is stretched from its equilibrium position. The block is then released from rest. Which of the following systems can be classified as a closed system?

A system consisting of the block, spring, and Earth

A student must determine the inertial mass of a block attached to a horizontal track. The block is free to move horizontally along the track, as shown above. Frictional forces are considered to be negligible. The student may only choose two measuring tools to determine the inertial mass of the block. What tools should the student choose? Select two answers.

Accelerometer, force sensor

A planet orbits a star in the path shown in the figure. The planet's mass is much smaller than the star's mass. Which two of the following claims are correct about the accelerations associated with the planet, star, and planet-star system? Select two answers. Justify your selections.

Both the planet and the star accelerate, because each object exerts a force on the other object. The center of mass of the planet-star system does not accelerate, because there is no net force exerted on the system.

A moon orbits a planet in a nearly circular orbit of radius RR, as shown in the figure. Which of the following free-body diagrams could be used to analyze the forces exerted on the moon when it is at the position indicated in the figure?

Dot with arrow to the right with only gravity

A horizontal, circular track for running has four lanes, as shown in the figure. Various runners of different masses use the track. In each case, the center of mass of a runner follows a circular path around the track in one of the lanes. Now consider four runners running around the track with the same constant tangential speed, with one runner in each lane of the track. A student is considering using the following equations to determine which runner has the greatest acceleration.

Equation 2, because the radius of the circular path traveled by a runner determines the acceleration of the runner.

A horizontal, circular track for running has four lanes, as shown in the figure. Various runners of different masses use the track. In each case, the center of mass of a runner follows a circular path around the track in one of the lanes. Consider a runner in lane 1 with a speed v1v1 and a runner in lane 4 with a speed v4v4, where the ratio of the speeds v4/v1v4/v1 is 22. The radius of lane 4 is bb times the radius of lane 1, and both runners have the same mass. Which of the following claims is correct about the net forces F1F1 and F4F4 exerted on the runners in lanes 1 and 4, respectively?

F4 is equal to 4/b F1

Planet X has a mass of MM and a radius of RR. Planet Y has a mass of 3M3M and a radius of 3R3R. Identical satellites orbit both planets at a distance RR above their surfaces, as shown above. The planets are separated by such a large distance that the gravitational forces between them are negligible. How does the magnitude of the gravitational force FYFY exerted by Planet Y on its satellite compare to the gravitational force FXFX exerted by Planet X on its satellite?

FY=3/4FX

Two satellites orbit a planet of mass MM, as shown above. Satellite AA of mass 2 m2 m travels in a circular orbit of radius RR. Satellite BB of mass mm travels in a circular orbit of radius 2 R2 R. Each satellite travels at a constant tangential speed. How does the gravitational force, FgAFgA, exerted on satellite AA from the planet compare with the gravitational force, FgBFgB, exerted on satellite BB from the planet?

FgA is larger than FgB because satellite A is twice as large as satellite B and is half the distance to the planet as satellite B

Three boxes are pulled to the left by strings with negligible mass on a horizontal surface, as shown above. The masses of the boxes are m1m1, m2m2, and m3m3, where m3>m2>m1m3>m2>m1. Friction between the boxes and the surface is negligible. The figure below shows force diagrams for each box. Which of the following is a correct ranking of the normal forces Fn1Fn1, Fn2Fn2, and Fn3Fn3 exerted on the boxes?

Fn3>Fn2>Fn1

A satellite orbits Earth in a circular path at a constant tangential speed, as shown in the figure. Which of the following correctly represents the directions of the net force FNetFNet , acceleration aa, and tangential velocity vTvT of the satellite at the instant shown in the figure?

Fnet up a up Vt right

One end of a vertical spring is attached to the ground with the other end above the ground such that the spring is at its equilibrium position. The spring has negligible mass and a spring constant k0k0 , as shown in Figure 1. When an object of mass m0m0 is released from rest above the spring, the object falls and then makes contact with the top of the spring with a speed v0v0 , as shown in Figure 2. The spring then compresses such that the object reaches a position x0x0 below the spring's equilibrium position, as shown in Figure 3, where the object comes to rest. The object is then directed upward by the spring until it is no longer in contact with the spring. The object then continues upward. The object-spring-Earth system has zero gravitational potential energy at the instant shown in Figure 2. All frictional forces are considered to be negligible. After the object reaches the position in Figure 3, the spring pushes the object upward until the object is no longer in contact with the spring. A graph of the force exerted by the spring on the object as a function of the position of the object is shown. How much work does the spring do on the object as it pushes the object upward until the object is no longer in contact with the spring?

FoXo/2

A student swings a ball of mass MM on the end of a string in a vertical circle of radius R, as shown in the top figure above. Also shown is a diagram representing all of the forces exerted on the ball at the bottom of the circle, where its speed is v0v0. What is the magnitude of the acceleration of the ball at the bottom of the circle?

Ftension-Fgravity/M

A block of mass MM is placed on a semicircular track and released from rest at point PP, which is at vertical height H1H1 above the track's lowest point. The surfaces of the track and block are considered to be rough such that a coefficient of friction exists between the track and the block. The block slides to a vertical height H2H2 on the other side of the track. How does H2H2 compare to H1H1?

H2<H1

One end of a string is attached to a ball, with the other end held by a student such that the ball is swung in a horizontal circular path of radius RR at a constant tangential speed. At a later time, the tension force exerted on the ball remains constant, but the length of the string is decreased to R4R4. What is the new tangential speed of the ball?

Half the original speed

A student must test the maximum force exerted on an object attached to a string before the string breaks. The student ties the object of mass m0m0 to one end of the string and then uses the other end of the string to spin the object at a constant speed so that the object travels in a horizontal circular path, as seen in Figure 1. Figure 2 shows the horizontal force exerted on the object at time t0t0. In a second trial, what should the student do to increase the tension in the string while keeping all other quantities constant? Select two answers.

Increase the mass of m0. Decrease the time required for one rotation.

A roller coaster track at a park includes a loop of radius RR. A cart of mass MM is located at the peak of the track, which has a height of 4R4R. The cart is subsequently released from rest such that it can slide down the track and go around the loop, as shown in the figure above. All frictional forces are considered to be negligible. Which of the following expressions for the cart's initial and final kinetic energy KEKE and the cart-Earth system's initial and final gravitational potential energy UgUg could be used to determine the speed vfvf of the cart when it reaches the top of the loop?

Initial Energy=4mgr ke=0 Final Energy2mgr ke=1/2mv^2

A student must determine the effect of friction on the mechanical energy of a small block as it slides up a ramp. The block is launched with an initial speed v0v0 from point A along a horizontal surface of negligible friction. It then slides up a ramp, where friction is not negligible, that is inclined at angle θθ with respect to the horizontal, as shown in the figure. The student measures the maximum vertical height hh attained by the block while on the ramp, labeled as point B in the figure. At point B, the block comes to rest. The student performs three trials with the ramp at different angles, launching the block at the same initial speed v0v0 for each trial. The results from the trials are displayed in the table. Consider the trial with the 45°45° ramp. Suppose the block is launched up the ramp such that it comes to rest at point BB and then travels down the ramp. Which of the following best describes the block's kinetic energy KAKA when it again reaches point AA at the bottom of the ramp in comparison to the initial kinetic energy K0K0 before it travels up the ramp?

KA<K0 , because the force of friction removes mechanical energy from the block-ramp-Earth system on its way up the ramp and back down the ramp.

An Atwood machine is placed on a planet in which the acceleration due to gravity on the planet is unknown. Both ends of a light string are attached to two blocks such that M1>M2M1>M2 , and the string passes through a pulley such that frictional forces are considered to be negligible, as shown above. The same tension force TT is exerted on both blocks, and the block of mass M1M1 experiences an acceleration a0a0 in the downward direction when released from rest. Which quantities would allow the acceleration due to gravity on the planet to be determined?

M1M1 , M2M2 , and a0

A rocket on Earth experiences an upward applied force from its thrusters. As a result of this force, the rocket accelerates upward at 2 m/s22 m/s2. Assume that there are no other upward forces exerted on the rocket and that wind resistance is negligible. Which of the following combinations of the rocket's mass mRocketmRocket and force from its thrusters FThrustersFThrusters would result in an upward acceleration of 2 m/s22 m/s2? Select two answers.

MRocket1kgFThrusters12N, MRocket3kgFThrusters36N

A block of mass MM slides with speed v0v0 at the bottom of a ramp of negligible friction that has a height HH, as shown. How do the total mechanical energy of the block alone and the total mechanical energy of the block-Earth system change when the block slides up the ramp to point PP?

Me block= decreases Me earthblock=constant

A toy car has a battery-powered fan attached to it such that the fan creates a constant force that is exerted on the car so that it is propelled in the opposite direction in which the fan blows air. The car has a carriage that allows a student to attach objects of different masses, as shown above. The fan has only one speed setting. All frictional forces are considered to be negligible. Which of the following procedures could be used to determine how the mass of the fan-car-object system affects the acceleration of the system?

Measure the mass of the system using a balance, activate the fan, measure the distance traveled by the system at a known time by using a stopwatch, and repeat the experiment for several trials with different objects added to the carriage.

A block of mass MM is attached to a modified Atwood machine and is accelerated upward at 3a3a by a constant force F0F0. What is the weight of the block?

Mg

Student XX ties one end of a string to a 0.50.5 kgkg ball and swings the ball in a vertical circle of radius 1 m1 ⁢m, as shown in the figure. Student YY uses video analysis to determine the speed of the ball at points AA, BB, CC, and DD, as shown in the table. Student XX states that the data are incorrect because the tension in the string provides a centripetal force that should cause the ball to travel with a constant tangential speed. Is Student XX's reasoning correct, and why or why not?

No, because the net centripetal force exerted on the ball is the combination of the tension force from the string and the force due to gravity from Earth.

A student uses a motion sensor to collect data about an object's velocity vv as a function of time tt after it is released from rest near Earth's surface. The student claims that the graph shown represents the object while in free fall. Does the data from the graph support the student's claim?

No, because the slope of the curve of the graph indicates that the acceleration is less than gg, which indicates that a force other than gravity is exerted on the object.

A block is placed on an inclined plane and remains stationary, as shown in the figure above. A student claims, "The block remains stationary because as gravity tries to pull the block down the ramp, the block exerts an equal and opposite force on itself up the ramp." Is the student's claim correct? Justify your answer.

No. Newton's third law states the block cannot exert a force on itself.

A toy car has an initial acceleration of 2m/s2 across a horizontal surface after it is released from rest. After the car travels for a time t=5t=5 seconds, the speed of the car is 25m/s. Is the system consisting of only the car an open system or a closed system, and why?

Open system, because an external force is applied to the car that causes it to accelerate.

A student performs an experiment in which a ball travels in a perfect circle. The ball is attached to a string and travels in the horizontal, circular path, as shown in Figure 1. At time t0t0, the ball has a speed ν0ν0. During the time interval of 0s0s to 2s2s, the force of tension in the string is recorded and graphed, as shown in Figure 2. Is the system consisting of the ball, string, and student an open system or closed system, and why?

Open system, because the force due to gravity from Earth is an external force that is exerted on the ball-string-student system

An object is placed on a rotating disk. The amount of time it takes the object to make one revolution around the center of the circle may be set at a known value. Which of the following procedures could be used to make the necessary measurements to find the coefficient of static friction between the object and the disk's surface?

Place the object on the disk and measure the distance from the center of the disk to the center of mass of the object by using a meterstick. Slowly increase the rate the disk rotates until the object begins to slide off the disk. Record the time in which the object makes one revolution around the center of the disk.

Identical spheres are dropped from a height of 100m100m above the surfaces of both Planet XX and Planet YY. The position of the spheres as a function of time is recorded as the spheres fall. These data are shown in the graphs above. Which planet exerts a greater gravitational force on the sphere, and what evidence supports this conclusion?

Planet YY, because the magnitude of the slope of the curve increases at a faster rate.

A rock of mass MM is thrown from the edge of a cliff of height hh with an initial velocity v0v0 at an angle θθ with the horizontal, as shown in the figure. Point PP is the highest point in the rock's trajectory, and point QQ is level with the initial position of the rock. All frictional forces are considered to be negligible. Which of the following could correctly describe the total energy of the rock-Earth system at points PP and QQ?

Point P=mgh+1/2mv^2 Point Q= mgh+1/2mv^2

A ball of Mass MM is swung in a vertical circle with a constant tangential speed. Figure 1 shows the forces exerted on the ball at the top of the circle, and Figure 2 shows the forces exerted on the ball at the bottom of the circle. Which of the following is an expression for the centripetal acceleration of the ball in terms of MM, T1T1, T2T2, and any fundamental constants?

T1+T2/2M

Three boxes are pulled to the left by strings with negligible mass on a horizontal surface, as shown above. The masses of the boxes are m1m1, m2m2, and m3m3, where m3>m2>m1m3>m2>m1. Friction between the boxes and the surface is negligible. The figure below shows force diagrams for each box. Given that m3>m2>m1m3>m2>m1, how do the force FF and string tensions TATA and TBTB compare?

TB<TA<F

A square block is attached to a string of negligible mass and moves in a horizontal circle at a constant speed. The string passes through a vertical tube, and its other end is attached to a cylinder, as shown in the figure. Which of the following claims can be made by relating one of Newton's laws of motion to an object that travels in uniform circular motion?

The block exerts a force on the string.

A long wooden board is at rest on a horizontal surface, and there is negligible friction between the board and the surface. A block is sliding along the board, and there is friction between the block and the board. At the instant shown in the figure, the block is moving but the board is still at rest. What happens to the board and block after the instant shown, and what reasoning supports this claim?

The board starts moving in the same direction as the block and the block is slowing down, because the board exerts a force on the block and the block exerts a force on the board.

An object is at rest on the ground. The object experiences a downward gravitational force from Earth. Which of the following predictions is correct about why the object does not accelerate downward? Select two answers. Justify your selections.

The bonded molecules of the object are repelled upward by the bonded molecules of the ground with the same magnitude as the gravitational force downward on the object. The normal force is exerted upward on the object from the ground with the same magnitude as the gravitational force downward on the object.

A 1500kg1500kg car traveling along a road is hit by a 0.1kg0.1kgrock that creates a small crack in the car's windshield. Which of the following describes the interaction between the windshield and the rock?

The car exerts a force on the rock, and the rock exerts a force on the car. The two forces are equal in magnitude.

Two students, Student XX and Student YY, stand on a long skateboard that is at rest on a flat, horizontal surface, as shown. In order to get the student-student-skateboard system to accelerate, Student XX claims that Student YY should apply a force on Student XX while both students stand on the skateboard. Which of the following statements is true regarding the claim made by Student XX?

The claim is incorrect because both students are internal to the student-student-skateboard system, and internal forces within a system cannot cause the system to accelerate.

A planet orbits a star along an elliptical path from point XX to point YY, as shown in the figure. In which of the following systems does the total mechanical energy of the system remain constant?

The closed system containing the planet and the star

Two objects, XX and YY, move toward one another and eventually collide. Object XX has a mass of 2M2M and is moving at a speed of 2v02v0 to the right before the collision. Object YY has a mass of MM and is moving at a speed of v0v0 to the left before the collision. Which of the following describes the magnitude of the forces FF the objects exert on each other when they collide?

The force exerted by XX on YY is FF to the right, and the force exerted by YY on XX is FF to the left.

A student pulls a block over a rough surface with a constant force FPFP that is at an angle θθ above the horizontal, as shown above. If FPFP remains constant but the angle θθ is increased, which of the following is true at some later time?

The force of friction between the block and surface will decrease.

Students connect a spring scale to a block on a rough horizontal surface. The students use the spring scale to measure the magnitude of the horizontal force needed to pull the block at a constant speed. Which of the following statements explains why two forces exerted between objects are equal in magnitude?

The frictional forces that the block and the surface exert on each other, because objects always exert forces of equal magnitude on each other.

A satellite orbits Earth. The only force on the satellite is the gravitational force exerted by Earth. How does the satellite's acceleration compare to the gravitational field at the location of the satellite? Select two answers.

The gravitational field and the acceleration point in the same direction. The magnitudes of the acceleration and the gravitational field strength are equal.

Objects XX and YY are connected by a string of negligible mass and suspended vertically over a pulley of negligible mass, creating an Atwood's machine, as shown in the figure. The objects are initially at rest, and the mass of object YY is greater than the mass of object XX. As object YY falls, how does the kinetic energy of the center of mass of the two-object system change? Justify your selection. All frictional forces are considered to be negligible.

The kinetic energy increases because the gravitational force due to Earth does positive net work on the system.

A spring-loaded launcher has a mass of 0.60 kg0.60 kg and is placed on a platform 1.2m1.2m above the ground. The force of friction is negligible between the platform and the launcher. The launcher fires a 0.30kg0.30kg ball that lands a distance DD to the right of the platform, as shown in the diagram above. Which of the following explanations is true?

The launcher will fall off the platform and land D/2 to the left of the platform because the launcher is twice the mass of the ball.

A small block of mass M=0.10 kgM=0.10 kg is released from rest at point 1 at a height H=1.8 mH=1.8 m above the bottom of a track, as shown in the diagram. It slides down the track and around the inside of a loop of radius R=0.6 mR=0.6 m. The speed of the block is 2.5 m/s2.5 m/s at point 3. Which of the following claims about the situation is correct?

The mechanical energy of the block-Earth system at point 3 is less than the mechanical energy of the block-Earth system at point 1.

A ball of mass MM is attached to a string of negligible mass that has a length RR. The ball moves clockwise in a vertical circle, as shown above. Which of the following is true about the ball-string-Earth system as the ball moves from point 1 to point 2?

The potential energy decreases by 2MgR and the tension in the string increases by more than 2Mg.

A 5 kg5 kg object near Earth's surface is released from rest such that it falls a distance of 10 m10 m. After the object falls 10 m10 m, it has a speed of 12 m/s12 m/s. Which of the following correctly identifies whether the object-Earth system is open or closed and describes the net external force?

The system is open, and the net external force is nonzero.

The total mechanical energy of a system as a function of time is shown in the graph. Which of the following statements is true regarding the system?

The system should be classified as an open system because mechanical energy can be added and removed from the system.

A student sets up an experiment to determine the inertial mass of a cart. The student has access to the following measurement equipment: a spring scale, a meterstick, and a stopwatch. The student uses the spring scale to pull the cart starting from rest along a horizontal surface such that the reading on the spring scale is always constant. All frictional forces are negligible. In addition to the spring-scale reading, which two of the following quantities could the student measure with the available equipment and then use to determine the inertial mass of the cart? Select two answers.

The total distance traveled by the cart after it has been in motion The time during which the cart is in motion

A student performs an experiment in which an applied force is exerted on a 4kg4kg object that is initially at rest. In the experiment, the applied force is exerted on the object until the object has moved a known distance. In all the experiments the applied force is exerted in the direction of motion. A motion detector measures the speed of the object after it has traveled the distance under consideration for a given trial. The table contains the data that were collected for three trials of the experiment. Which of the following conclusions can be drawn from the data? Select two answers.

The total mechanical energy after a given trial is equal to the kinetic energy of the object at the end of the experiment. Another external force must have done work on the object because the final kinetic energy of the object is less than the work done on the object by the applied force.

An experiment is conducted such that an applied force is exerted on an object as it travels across a horizontal surface with a constant speed. A graph of the applied force exerted on the object as a function of the object's distance traveled is shown. Which of the following claims is correct regarding the work done on the object by the applied force from one data point to the next data point?

The work done remains nearly constant for all displacements.

A moon orbits a planet in a nearly circular orbit of radius RR, as shown in the figure. Astronomers making careful observations of the moon's orbit discover that the orbit is not perfectly circular, nor is it elliptical. Which of the following statements supports this observation?

There is another celestial body that exerts a gravitational force on the moon.

A student uses an electronic force sensor to study how much force the student's finger can apply to a specific location. The student uses one finger to apply a force on the sensor, and data collected from two trials are shown in the table. During which trial, if any, does the student's finger experience the greatest electromagnetic force?

Trial 2, because the student's finger applied the largest force to the sensor.

A student must determine the effect of friction on the mechanical energy of a small block as it slides up a ramp. The block is launched with an initial speed v0v0 from point A along a horizontal surface of negligible friction. It then slides up a ramp, where friction is not negligible, that is inclined at angle θθ with respect to the horizontal, as shown in the figure. The student measures the maximum vertical height hh attained by the block while on the ramp, labeled as point B in the figure. At point B, the block comes to rest. The student performs three trials with the ramp at different angles, launching the block at the same initial speed v0v0 for each trial. The results from the trials are displayed in the table. Consider the trial in which the ramp is at a 20°20° angle with the horizontal. The surface of the ramp has been replaced with a surface in which frictional forces are considered to be negligible. If the mass of the block is doubled and the initial launch speed is doubled, how could the student predict the new vertical of the block at point BB?

Use 1/2mv^2initial=mgyfinal to solve for yf.

A student must determine the effect of friction on the mechanical energy of a small block as it slides up a ramp. The block is launched with an initial speed v0v0 from point A along a horizontal surface of negligible friction. It then slides up a ramp, where friction is not negligible, that is inclined at angle θθ with respect to the horizontal, as shown in the figure. The student measures the maximum vertical height hh attained by the block while on the ramp, labeled as point B in the figure. At point B, the block comes to rest. The student performs three trials with the ramp at different angles, launching the block at the same initial speed v0v0 for each trial. The results from the trials are displayed in the table. How should the student use the data collected and the known quantities from the experiment to determine the initial total mechanical energy of the block-ramp-Earth system for all trials in the experiment?

Use K=1/2mv^2 with the block's initial speed for one trial because the initial speed is the same in all trials

A student must determine the work done on an object when an external force is exerted on it after it travels a specific distance. An external force FF is exerted on an object at position x = 0x = 0 by a string as the object moves a distance DD across a horizontal surface for a time tftf . The force changes such that it decreases as the object moves. Which procedure could be used to determine the work done on the object by the external force?

Use a spring scale that is tied to the free end of the string and a meterstick to measure the force exerted on the object and the corresponding position for several positions until the object travels a distance DD . Graph the force on the vertical axis and the position on the horizontal axis. Determine the area bound by the curve and the horizontal axis.

Which of the following experiments could be used to determine the inertial mass of a block?

Use a spring scale to exert a force on the block. Measure the acceleration of the block and the applied force.

An object falls toward Earth after it is released from rest, as a result of Earth's gravitational force. A student uses a motion detector to create the graph of the object's displacement as a function of the squared time in which the object was in free fall. How can the student use the graph to determine the acceleration ayay of the object while in free fall?

Use the slope of the graph and set it equal to 1/2ay to then solve for ay.

A student uses a motion detector to record the speed of a 2kg2kg object as a function of time as it travels across a horizontal surface of negligible friction. Data from the experiment are shown in the graph. In addition to the known mass, how can a student use the graph to determine the work done on the object from 0s0s to 5s5s ?

Use ΔK=1/2mΔv^2 with v0 equal to the speed of the object at 0s0s and vf equal to the speed of the object at 5s

The amusement park ride shown above takes riders straight up a tall tower and then releases an apparatus holding seats. This apparatus free-falls back to Earth and is stopped safely right above the ground. Which of the following indicates the magnitude of the gravitational force exerted on a rider of mass mm on the way up and on the way down?

Way up- equal to mg way down- equal to mg

A block on a rough, horizontal surface is attached to a horizontal spring of negligible mass. The other end of the spring is attached to a wall. The spring is compressed such that the block is located at position XX. When the block-spring system is released, the block travels to the right through position YY and continues to travel to the right through position ZZ. Free body diagrams for the block at positions XX, YY, and ZZ are shown in the figure. At which position does the block have the greatest kinetic energy?

Y

A student analyzes data of the motion of a planet as it orbits a star that is in deep space. The orbit of the planet is considered to be stable and does not change over time. The student claims, "The only experimentally measurable external force exerted on the planet is the force due to gravity from the star." Is the student's claim supported by the evidence? What reasoning either supports or contradicts the student's claim?

Yes. Other external forces are exerted on the planet, but they are of negligible magnitude.

Block AA is placed on a rough surface inclined at an angle θθ above the horizontal. A taut string connects block AA over a pulley to block BB, which hangs from the string, as shown below. The masses of blocks AA and BB are MAMA and MBMB, respectively. At time t=0t=0, block AA is sliding up the slope as block BB falls, and the blocks are both slowing down. Assume that the mass and friction of the pulley are negligible. The two blocks eventually stop and reverse direction. Which of the following graphs best predicts the acceleration of block AA as it moves up and down the rough, inclined surface? Assume that the positive direction points down the slope.

___________ ______________ ...............................................x axis

A horizontal, circular track for running has four lanes, as shown in the figure. Various runners of different masses use the track. In each case, the center of mass of a runner follows a circular path around the track in one of the lanes. Consider a runner in any of the lanes moving at a known, constant tangential speed. Which of the following measuring tools, if any, could be used to experimentally determine the centripetal acceleration of the runner?

a meterstick

A student conducts three experiments to determine how certain quantities influence the centripetal force responsible for an object to spin in a horizontal circle. The student uses one end of a string to attach the object while the other end is connected to a force sensor that allows the student to change the tension on the string, as shown in the figure. The student records data from the three experiments in the table above. Which of the following experiments, if any, collected data that do not agree with the expression for the net centripetal force on the object?

all the data are expected

Satellite AA orbits a planet at a distance dd from the planet's center with a centripetal acceleration a0a0. A second identical satellite BB orbits the same planet at a distance 2d2d from the planet's center with centripetal acceleration abab. What is the centripetal acceleration abab in terms of a0a0 ?

ao/4

Two experiments are conducted are conducted to determine the mass of an object. In Experiment 1, the object's weight is measured by using an electronic balance once the object has been placed at rest on the balance. In Experiment 2, the object is pulled along a horizontal surface with a spring scale such that the force reading on the spring scale remains constant while a motion detector is used to measure the instantaneous speed of the object as it is pulled. All frictional forces for both experiments are considered to be negligible. Which of the two experiments, if either, could be used to determine the gravitational mass of the object?

experiment 1 only

Planet X has a mass of MM and a radius of RR. Planet Y has a mass of 3M3M and a radius of 3R3R. Identical satellites orbit both planets at a distance RR above their surfaces, as shown above. The planets are separated by such a large distance that the gravitational forces between them are negligible. How does the gravitational field gXgX at the surface of Planet X compare with the gravitational field gYgY at the surface of Planet Y?

gX=3gY

A small object of mass MM is shot horizontally from a spring launcher that is attached to a table. All frictional forces are considered to be negligible. The ball strikes the ground a distance DD from the base of the table, as shown in the figure. A second object of mass M2M2 is launched from the same launcher such that the spring is compressed the same distance as in the original scenario. The distance from the base of the table that the object lands is

greater than D but less than 2D

Planet XX is in a stable circular orbit around a star, as shown above. Which of the following graphs best shows the tangential speed of the planet as a function of its horizontal position from point AA to point BB if the planet is moving counter clockwise as viewed in the figure above?

horizontal line above x axis

One end of a vertical spring is attached to the ground with the other end above the ground such that the spring is at its equilibrium position. The spring has negligible mass and a spring constant k0k0 , as shown in Figure 1. When an object of mass m0m0 is released from rest above the spring, the object falls and then makes contact with the top of the spring with a speed v0v0 , as shown in Figure 2. The spring then compresses such that the object reaches a position x0x0 below the spring's equilibrium position, as shown in Figure 3, where the object comes to rest. The object is then directed upward by the spring until it is no longer in contact with the spring. The object then continues upward. The object-spring-Earth system has zero gravitational potential energy at the instant shown in Figure 2. All frictional forces are considered to be negligible. Which of the following describes the total mechanical energy of the object-Earth system during the time in which the object is in the air and the time in which the object is in contact with the spring? Assume all frictional forces are considered to be negligible.

in air=constant contact with spring=not constant

The figure above shows two identical asteroids that are located near each other but are not in contact. Various locations are also labeled on the asteroids. If an astronaut wants to stand on one of the asteroids and experience the largest net gravitational force, where should the astronaut stand?

location a

Three boxes are pulled to the left by strings with negligible mass on a horizontal surface, as shown above. The masses of the boxes are m1m1, m2m2, and m3m3, where m3>m2>m1m3>m2>m1. Friction between the boxes and the surface is negligible. The figure below shows force diagrams for each box. A student is trying to determine the tensions in the strings connecting the boxes. If the acceleration of the system and the pulling force FF are known, which of the following pairs of equations could be used to find the tensions?

m3a3=TB and m2a2=TA−TB

A planet orbits a star along an elliptical path, as shown in the figure. Consider the system consisting of the planet and the star. How do the magnitude of the force exerted on the planet by the star and the total mechanical energy of the system change as the planet moves from point XX to point YY?

magnitude of force=increases me= remains constant

A student must perform an experiment to determine the work done by a spring as it launches a block across a horizontal surface. The spring is initially compressed and the block is initially held at rest. After the spring is uncompressed, the block is no longer in contact with the spring. The spring constant is unknown, and the student may not use the mass or weight of the block in the experiment for any calculation. Which of the following measuring tools, when used together, can be used to determine the work done by the spring on the block? Select two answers.

meterstick and force sensor

A block is at rest on a disk that spins about its center, as shown. A student must determine the centripetal acceleration of the block when the block spins with the disk as a result of the force of static friction. What measuring devices, when used together, could be used to determine the centripetal acceleration of the block? Select two answers.

meterstick and stopwatch

A student must conduct two experiments so that the inertial mass and gravitational mass of the same object can be determined. In the experiment to find the object's gravitational mass, the student ties one end of a string around the object with the other end tied to a spring scale so that the object can vertically hang at rest. In the experiment to find the object's inertial mass, the student uses a spring scale to pull the object, starting from rest, across a horizontal surface with a constant applied force such that frictional forces are considered to be negligible. In addition to the spring scale, the student has access to other measuring devices commonly found in a science laboratory. Which of the following lists the essential measuring devices the student can use to collect the data necessary to find the object's gravitational and inertial mass?

meterstick and timer

A block of mass MM is held at rest on an inclined ramp that can be considered frictionless. The ramp makes an angle θθ with the horizontal, as shown in Figure 1. When released, the block slides down the incline and comes into contact with an uncompressed spring with spring constant k0k0 . The block slides an additional distance x0x0 before it compresses the spring a maximum distance, as shown in Figure 2. A student wants to use the law of conservation of energy to analyze the energies associated with the block-ramp-spring-Earth system. Which of the following equations should the student use to analyze the specific forms of energy in the system from the instant the block is released to the instant that the spring is at its maximum compression? Select two answers.

mg(y0−yf)=1/2kx^2 , because the initial gravitational potential energy of the system is converted into spring potential energy. mgy0=mgyf+1/2kx^2, because some of the initial gravitational potential energy of the system is converted into spring potential energy.

A block is initially sliding along a surface of negligible friction with a speed v0v0. A constant force F0F0 is then exerted on the block. Which of the following figures represents the situations in which the kinetic energy of the block will initially decrease? Select two answers.

obtuse angles

A truck in a traffic circle travels in a circular path at constant speed v0v0 while passing through region XX of the circle, as shown in Figure 1 above. A diagram representing the forces exerted on the truck in region XX is shown in Figure 2. At a later time a car with less mass than the truck passes through region XX at the same speed and the same distance from the center of the traffic circle as the truck. The coefficient of friction between the car's tires and the ground is the same as that for the truck's tires and the ground. Which of the following diagrams could represent the forces exerted on the car in region XX compared to the truck in region XX ? Assume that the length of each arrow is proportional to the magnitude of the force represented by the arrow.

small friction force with small fgrav and fnorm

An object of mass MM is placed on a disk that can rotate. One end of a string is tied to the object while the other end of the string is held by a pole that is located at the center of the disk. Initially, the object is spun in a horizontal circle of radius RR at a constant tangential speed of v0v0, as shown in the figure, such that the tension in the string is TT. At a later time, the disk is spun such that the tangential speed of the object is increased to 2v02v0 . At a later time, the tangential speed of the object is increased to 3v03v0 . Which of the following diagrams could represent the forces exerted on the object at one of the given speeds? Assume that the force of static friction is negligible. Select two answers.

the ones with 4t and 9t

Two identical blocks, block A and block B, are placed on different horizontal surfaces. Block A is initially at rest on a smooth surface, while block B is initially at rest on a rough surface. A constant horizontal force of magnitude F0F0 is exerted on each block. After the force has been applied for a time ΔtΔt, the speeds of blocks A and B are vAvA and vBvB, respectively. Which of the following claims indicates the correct relation between vAvA and vBvB and provides the best justification for the relation?

vA>vB. The forces between the atoms in a block and the atoms in a surface oppose the motion of the block and are greater, on average, for block B.

A satellite moves in a circular orbit at a constant speed v0v0 around Earth at a distance RR from its center. The force exerted on the satellite is F0F0. An identical satellite orbits Earth at a distance of 3R3R from the center of the Earth. How does the tangential speed, vTvT, of the satellite at distance 3R3R compare to the speed v0v0 of the satellite at RR?

vT=1/√3v0

A cart of mass MM travels from point AA at height h1h1 above the ground to point BB on a track that is at a height h2h2, as shown in the figure. The speed of the cart at point AA is nearly zero, and the frictional forces between the wheels, cart, and track are considered to be negligible. Which of the following graphs could represent the potential energy of the cart-Earth system at point AA and point BB? Select two answers.

where point a is higher