AP Physics

A car initially at rest accelerates at 10m/s^2. The car's speed after it has traveled 25 meters is most nearly

22.0 m/s

A ball is released from rest from the twentieth floor of a building. After 1 s, the ball has fallen one floor such that it is directly outside the nineteenth-floor window. The floors are evenly spaced. Assume air resistance is negligible. What is the number of floors the ball would fall in 3s after it is released from the twentieth floor?

7 to 10 floors

An object undergoes an acceleration as it travels along a straight, horizontal section of a track. Which of the following graphs could represent the motion of the object? Select two answers.

Both graphs with a positive slope that do not start at (0,0)

An object travels along a straight, horizontal surface with an initial speed of 2 m/s. The velocity of the object as a function of time is given in the table above. Which of the following graphs represents the object's acceleration as a function of time?

Graph with a slope of 0 at y=2.0

A student uses a motion sensor to collect data of the velocity of an object as a function of time during two experimental trials, as shown. In which trial does the object have the greatest magnitude of acceleration, and in which trial does the object travel the greatest distance?

Greatest Magnitude of Acceleration: Trial 2 Greatest Distance: Trial 1

A tennis ball is thrown against a vertical concrete wall that is fixed to the ground. The ball bounces off the wall. How does the force exerted by the ball on the wall compare with the force exerted by the wall on the ball?

The forces exerted by the ball and the wall have the same magnitude.

A student drops a rock from the top of a cliff such that the rock falls downward toward Earth's surface in the absence of air resistance. The downward direction is considered to be the positive direction. The graph shows the rock's velocity as a function of time. Which of the following methods should be used to determine the total distance traveled by the rock after 4s?

Use the area under the curve, as it states that the rock traveled 80 meters in total.

An object is released from rest near a planet's surface. A graph of the acceleration as a function of time for the object is shown for the 4 s after the object is released. The positive direction is considered to be upward. What is the displacement of the object after 2 s?

-10 m

An object is sliding to the right along a straight line on a horizontal surface. The graph shows the object's velocity as a function of time. What is the object's displacement during the time depicted in the graph?

0 m

At time t=0, a moving cart on a horizontal track is at position 0.5m. Using a motion detector, students generate a graph of the cart's velocity as a function of time, as shown above. At t=2.5s, the cart's position is most nearly

1.75 m

An object is dropped from the top of a building near Earth's surface. After 2 s, a second identical object is dropped from the same building from the same height. After 4 s, the first object strikes the ground. The graph shows the speeds ν of both objects as a function of time t. What is the approximate acceleration of the center of mass of the two-object system at the moment right before the first object reaches the ground?

10 m/s^2

Identical objects, Object X and Object Y, are tied together by a string and placed at rest on an incline, as shown in the figure. The distance between the center of mass of each object is 2m. The system of the two objects is released from rest, and a graph of the system's center of mass velocity as a function of time is shown. Based on the data, approximately how much time will it take the center of mass of Object X to reach point J near the bottom of the incline?

3.0 s

An object rotates at various distances from the center of a disk such that the object experiences a force of friction from the disk. Data collected from the experiment are shown in the table above. Each location of the disk rotates such that the tangential speed at that point remains constant. What is the magnitude of the force of friction exerted on the object if its mass is doubled and it is placed at a distance of 0.6 m from the disk's center?

3.6 N

A ball traveling at a speed ν0 rolls off a desk and lands at a horizontal distance x0 away from the desk, as shown in the figure. The ball is then rolled off of the same desk at a speed of 3 v0. At what horizontal distance will the ball land from the table?

3x0

A student drops a rock from rest at a distance h above the ground such that the rock hits the ground at time t0. At what distance above the ground should the rock be dropped such that it hits the ground at a time 2t0 after it is released from rest?

4h

A student wants to investigate the motion of a ball by conducting two different experiments, as shown in Figure 1 and Figure 2 above. In Experiment 1, the student releases a ball from rest and uses a slow-motion camera to film the ball as it falls to the ground. Using video analysis, the student is able to plot the ball's horizontal position x and vertical position y as a function of time t. In Experiment 2, the student horizontally rolls the same ball off a table, and uses video analysis to plot the ball's horizontal position x and vertical position y as a function of time t starting from the instant the ball leaves the table. The graphs from each experiment are shown above along with each graph's best-fit curve line. In Experiment 1, what is the speed of the ball the instant it makes contact with the ground?

5.4 m/s

A student performs an experiment in which the horizontal position of a toy car is recorded on ticker tape from a device that places dots on the tape in equal time intervals. The series of dots in the figure represents the motion of an object moving from the negative direction to the positive direction along the horizontal direction. The time interval between each recorded dot is 1s. Which of the following experiments could the student have conducted to create the data shown on the ticker tape?

A toy car that initially increases its speed, travels at a constant speed, and then decreases its speed.

Object 1 and object 2 travel across a horizontal surface, and their horizontal velocity as a function of time is shown in the graph. Which of the following statements is correct about the two-object system?

After 2s, object 1 travels a greater distance than object 2 travels.

Car X and car Y travel on a horizontal surface along different parallel, straight paths. Each car's velocity as a function of time is shown in the graph. Which of the following claims is correct about car X and car Y?

Both car X and car Y travel in the same direction.

A student wants to launch a toy dart toward a target that hangs from a light string. At time t=0, the dart is launched with an initial speed v0 at an angle θ0 above the horizontal ground. At the instant the dart is launched, the string is cut such that the target begins to fall straight down. The positive horizontal direction is considered to be to the right, and the positive vertical direction is considered to be up. Figure 1 shows a displacement-versus-time graph for the dart. Figure 2 shows a displacement-versus-time graph for the target. For both graphs, the component of the displacement is not indicated. Which displacement component, horizontal or vertical, is represented by the graph for each object?

Dart: Vertical Target: Vertical

A student wants to investigate the motion of a ball by conducting two different experiments, as shown in Figure 1 and Figure 2 above. In Experiment 1, the student releases a ball from rest and uses a slow-motion camera to film the ball as it falls to the ground. Using video analysis, the student is able to plot the ball's horizontal position x and vertical position y as a function of time t. In Experiment 2, the student horizontally rolls the same ball off a table, and uses video analysis to plot the ball's horizontal position x and vertical position y as a function of time t starting from the instant the ball leaves the table. The graphs from each experiment are shown above along with each graph's best-fit curve line.

Equal to g

Blocks A and B, of masses m and 2m, respectively, are connected by a light string and pulled across a surface of negligible friction with a constant force F1, as shown above. The acceleration of the blocks is a. The force of the string pulling block B forward has magnitude F2. Which of the following claims correctly describes the relationship between the magnitude of the forces acting on the blocks?

F1 is greater than F2.

Object X and object Y are at rest on a horizontal surface. Object X is in contact with object Y. The force diagrams for both objects are shown above. Which two forces make up an action-reaction pair?

F3 and F6, because both forces are exerted on different objects, have the same magnitude, and are in opposite directions.

A stick is used to hit a ball at an angle above the horizontal, as shown in Figure 1. Figure 2 shows the free body diagram of the ball. Figure 3 shows the free body diagram of the stick. Which of the following pairs of forces represents an action-reaction pair and the object or objects involved in the action-reaction pair?

FStick and FBall

The diagram above represents the forces exerted on a box that a child is holding. FN represents the force applied by the child's hand, and Fg represents the weight of the box. The child begins to raise the box with increasing speed. Which of the following claims is correct about force Fh that is exerted by the box on the child's hand as the box is being raised?

Fh=FN, where FN is larger as the box is being raised than when it was being held.

A student wants to launch a toy dart toward a target that hangs from a light string. At time t=0, the dart is launched with an initial speed v0 at an angle θ0 above the horizontal ground. At the instant the dart is launched, the string is cut such that the target begins to fall straight down. The positive horizontal direction is considered to be to the right, and the positive vertical direction is considered to be up. A student makes the necessary measurements to create the graph shown, which represents the vertical component of the velocity as a function of time for the dart and for the target from t=0 until the instant the dart hits the target. At t=0, the target is a vertical distance h above the dart. The curves for the dart and the target each have the same area between them and the horizontal axis. Both curves also have the same slope. Which of the following is the best method to determine the distance h from the graph?

Find twice the area under the curve for the dart's data.

An object travels along a straight line across a horizontal surface, and its motion is described by the velocity versus time graph shown in the figure. Which of the following methods will determine the total displacement of the object between

Finding the area bound by the horizontal axis and the curve from 0 s to 5 s Using Average Speed = total distance/total and multiplying the average speed by 5 m/s by a total time of 5 s

Rock X is released from rest at the top of a cliff that is on Earth. A short time later, Rock Y is released from rest from the same location as Rock X. Both rocks fall for several seconds before landing on the ground directly below the cliff. Frictional forces are considered to be negligible. Which of the following graphs best represents the vertical displacement of Rock X as a function of time starting from immediately after the rock is released from rest? Take the positive direction to be downward.

Graph that is concave up that begins at (0,0)

Rock X is released from rest at the top of a cliff that is on Earth. A short time later, Rock Y is released from rest from the same location as Rock X. Both rocks fall for several seconds before landing on the ground directly below the cliff. Frictional forces are considered to be negligible. Which of the following graphs correctly shows the vertical velocity of rock X as a function of time? Take the positive direction to be upward.

Graph with a constant negative slope that starts at (0,0)

An object travels along a straight, horizontal surface with an initial speed of 2 m/s. The position of the object as a function of time is given in the table. Which of the following graphs represents the object's velocity as a function of time?

Graph with a constant slope of 2 that has a y-intercept at y=2

A potato falling vertically downward is struck by a dart that is traveling vertically upward, as shown above. The dart and potato then collide, stick together, and continue moving after the collision. The weight of the dart is W. Which of the following claims best describes the magnitude of the net force on the dart immediately before, during, and immediately after the collision with the potato?

It is equal to W just before the collision, greater than W during the collision, and equal to W again after the collision.

A student must determine the relationship between the inertial mass of an object, the net force exerted on the object, and the object's acceleration. The student uses the following procedure. The object is known to have an inertial mass of 1.0kg. Step 1: Place the object on a horizontal surface such that frictional forces can be considered to be negligible. Step 2: Attach a force probe to the object. Step 3: Hang a motion detector above the object so that the front of the motion detector is pointed toward the object and is perpendicular to the direction that the object can travel along the surface. Step 4: Use the force probe to pull the object across the horizontal surface with a constant force as the force probe measures force exerted on the object. At the same time, use the motion detector to record the velocity of the object as a function of time. Step 5: Repeat the experiment so that the object is pulled with a different constant force. Can the student determine the relationship using this experimental procedure?

No, because the motion detector should be oriented so that the object moves parallel to the line along which the front of the motion detector is aimed.

An astronaut in deep space is at rest relative to a nearby space station. The astronaut needs to return to the space station. A student makes the following claim: "The astronaut should position her feet pointing away from the space station. Then, she should repeatedly move her feet in the opposite direction to each other. This action will propel the astronaut toward the space station." Is the student's claim correct? Justify your selection.

No. The astronaut's feet are not exerting a force on another object, so there is no external force to accelerate the astronaut toward the space station.

A student is provided with a battery-powered toy car that the manufacturer claims will always operate at a constant speed. The student must design an experiment in order to test the validity of the claim. Which of the following measuring tools can the student use to test the validity of the claim? Select two answers.

Photogates placed at the beginning, end, and at various locations along the track that the car travels on A meterstick to measure the distance of the track that the car travels on

A motion sensor is used to create the graph of a student's horizontal velocity as a function of time as the student moves toward and away from the sensor, as shown above. The positive direction is defined as the direction away from the sensor. Which of the following describes the student's final position xf in relation to the starting position x0 and the student's average horizontal acceleration ax between 0.0 s and 3.0s?

Position xf is farther away from the sensor than x0, and ax is negative.

A student wants to study the motion of an object that has a constant acceleration. Which of the following experiments could the student conduct to provide the best situations in which an object has a constant acceleration? Select two answers.

Release a ball from rest near Earth's surface. Release a cart from rest such that it travels down an incline of 40° with respect to the ground.

Rock X is released from rest at the top of a cliff that is on Earth. A short time later, Rock Y is released from rest from the same location as Rock X. Both rocks fall for several seconds before landing on the ground directly below the cliff. Frictional forces are considered to be negligible. After Rock Y is released from rest several seconds after Rock X is released from rest, what happens to the separation distance S between the rocks as they fall but before they reach the ground, and why? Take the positive direction to be downward.

S increases because at all times Rock X falls with a greater speed than Rock Y.

A student wants to investigate the motion of a ball by conducting two different experiments, as shown in Figure 1 and Figure 2 above. In Experiment 1, the student releases a ball from rest and uses a slow-motion camera to film the ball as it falls to the ground. Using video analysis, the student is able to plot the ball's horizontal position x and vertical position y as a function of time t. In Experiment 2, the student horizontally rolls the same ball off a table, and uses video analysis to plot the ball's horizontal position x and vertical position y as a function of time t starting from the instant the ball leaves the table. The graphs from each experiment are shown above along with each graph's best-fit curve line. Which of the following conclusions can the student draw from the graphs, and why?

Since the balls have the same vertical position at any given time, they reach the ground at the same time.

A student must design an experiment to determine the relationship between the mass of an object and the resulting acceleration when the object is under the influence of a net force. Which of the following experiments should the student conduct in order to determine the relationship between all three quantities?

Slide an object of known mass across a rough surface, using a constant applied force that can be measured by a force sensor. Place a motion detector behind the object so that its speed can be measured as it slides across the surface. Repeat the experiment for different applied forces.

The system shown above consists of two identical blocks that are suspended using four cords, each of a different length. Which of the following claims are true about the magnitudes of the tensions in the cords? Select two answers.

T1cos30°=T2cos60° T3>T4

Two blocks are tied together with a string. They are thrown onto a layer of ice such that they spin around their center of mass C as they slide horizontally across the icy surface, as shown in the figure. A graph of the two-block system's velocity as a function of time is shown. Based on the graph, which of the following claims are correct about the system? Select two answers.

The acceleration of the center of mass of the system is constant. The system's acceleration vector is opposite to the direction of the system's velocity vector.

Two blocks are connected by a rope, as shown above. The masses of the blocks are 5 kg for the upper block and 10 kg for the lower block. An upward applied force of magnitude F acts on the upper block. The system is moving and accelerating upward. A pair of scissors cuts the rope. Which of the following describes the motion of the 10 kg block immediately after the rope has been cut?

The block continues to move upward but begins to accelerate downward.

A student uses both hands to push a door such that it moves and swings open after the force has been applied. The student then makes the following claim: "I can use both of my hands to apply a constant force on my body so that my body falls backward." Which of the following statements correctly justifies the student's claim?

The claim is not correct because the student's body will exert a force of equal magnitude back on the student's hands as a result of Newton's third law of motion.

A student wants to launch a toy dart toward a target that hangs from a light string. At time t=0, the dart is launched with an initial speed v0 at an angle θ0 above the horizontal ground. At the instant the dart is launched, the string is cut such that the target begins to fall straight down. The positive horizontal direction is considered to be to the right, and the positive vertical direction is considered to be up. Which of the following graphs could represent the vertical component of the velocity as a function of time for the dart and the target immediately after the dart is launched and the target begins to fall?

The dart should be in the positive quadrant with a negative slope while the target should be in the negative quadrant with a negative slope.

A ladybug is crawling up a wall at constant speed, as shown above. Which of the following are correct justifications for how forces help the ladybug move up the wall? Select two answers.

The ladybug exerts a downward force on the wall to move itself up the wall. The upward force of the wall on the ladybug moves the ladybug up the wall.

A ball is dropped onto the floor and bounces upward. Which of the following claims are correct about the force that the ball exerts on the floor compared to the force that the floor exerts on the ball when the ball and the floor are in contact?

The magnitude of the forces exerted by both objects is the same because the ball and the floor cannot exert forces of different magnitudes on each other.

An object is launched upward at angle θ0 above the horizontal with a speed of v0. The trajectory and three positions of the object, X, Y, and Z, are shown in the figure. Position X is higher than position Z with respect to the ground, and position Y is at the object's maximum vertical position. Which of the following claims is correct about the system that consists of only the object?

The object's acceleration is the same at positions X, Y, and Z.

Students work together during an experiment about Newton's laws. The students use a setup that consists of a cart of known mass connected to one end of a string that is looped over a pulley of negligible friction, with its other end connected to a hanging mass. The cart is initially at rest on a horizontal surface and rolls without slipping when released. The inertia of the cart's wheels is negligible. Students have access to common laboratory equipment to make measurements of components of the system. The students double the mass that hangs from the string. They also replace the original cart with a new cart that has double the mass. By doubling both masses, how will the tension in the string and the acceleration of the cart change?

The tension will double, but the acceleration will stay the same.

Two identical books are stacked on a table. A third identical book is then placed on top of the first two, causing an increase in the normal force exerted by the bottom book on the middle book. Which of the following is a correct explanation for the increase in this normal force?

The third book produces an additional downward force on the middle book, thus increasing the upward force exerted by the bottom book to maintain equilibrium.

A cart with an unknown mass is at rest on one side of a track. A student must find the mass of the cart by using Newton's second law. The student attaches a force probe to the cart and pulls it while keeping the force constant. A motion detector rests on the opposite end of the track to record the acceleration of the cart as it is pulled. The student uses the measured force and acceleration values and determines that the cart's mass is 0.4kg. When placed on a balance, the cart's mass is found to be 0.5kg. Which of the following could explain the difference in mass?

The track was not level and was tilted slightly downward.

In one experiment, a student rolls a 2 kg ball such that it collides with a wall with a force of 10,000 N. In a second experiment, the student rolls a 5 kg ball such that it collides with the wall at a force of 5000 N. In both experiments, the balls bounce back from the wall and eventually come to rest. Which of the following statements is true regarding the force that the wall exerts on each ball?

The wall exerts a greater force on the 2 kg ball than on the 5 kg ball since the force from the wall on each ball is equal to the force that each ball exerts on the wall.

A student must design an experiment to determine the acceleration of a cart that rolls down a small incline after it is released from rest. The student has access to a timer, a meterstick, and a slow-motion camera that takes a photograph every 1/60 of a second. The angle that the incline makes with the horizontal is unknown, and the length of the incline is unknown. Which of the following procedures could the student use to determine the cart's acceleration? Select two answers.

Use the timer to record the time it takes the cart to travel alongside a meterstick that is attached to the incline. Use the slow-motion camera to film the cart as it rolls down the incline alongside a meterstick that is attached to the incline.

Two students want to determine the speed at which a ball is released when thrown vertically upward into the air. One student throws the ball into the air while the other student measures the total time that the ball is in the air. The students use a meterstick to measure the release height of the ball. Which of the following equations should the students use to determine the speed at which the ball was released?

Use y=t0+vy0t+1/2at^2 from the moment in time in which the ball was released to the moment in time in which the ball hits the ground.

The table shows the vertical position as a function of time for an object that is dropped from a height of 5 m. A student must determine the acceleration of the object. Which of the following procedures could the student use to make the determination? Justify your selections. Select two answers.

Use y=y0+vy0t+1/2ayt^2, since all quantities are known except for the acceleration due to gravity. Create a position-versus-time graph of the ball's motion, and use the data to create a velocity-versus-time graph of the ball's motion, since the slope of the velocity-versus-time graph represents the acceleration.

Identical objects, object X and object Y, are tied together by a string and placed at rest on an incline, as shown in the graph. The string has a length of 2 m. The system of the two objects is released from rest, and a graph of the velocity of the center of mass of the system as a function of time is shown in the figure. If the string was cut and object Y was released from rest while object X was held at rest, which of the following claims is correct about the new acceleration of the center of mass of system anew compared to the original acceleration of the center of mass of the system aoriginal?

anew will be less than aoriginal

A bowling pin is thrown vertically upward such that it rotates as it moves through the air, as shown in the figure. Initially, the center of mass of the bowling pin is moving upward with a speed vi of 10 m/s. The maximum height of the center of mass of the bowling pin is most nearly

vi^2/2g

Two objects, object X and object Y, are held together by a light string and are released from rest near a planet's surface in the orientation that is shown in the figure. Object X has a greater mass than object Y. A graph of the acceleration as a function of time for the system's center of mass is shown for the 4s. The positive direction is considered to be upward. How does the speed of object X vx compare to that of the system's speed vs after the objects have fallen for 4s?

vx=vs

An object is held at an unknown height above Earth's surface, where the acceleration due to gravity of the object is considered to be constant. After the object is released from rest, a student must determine the object's speed the instant the object makes contact with the ground. Which of the following equations could the student use to determine the object's speed by using the fewest measuring tools if the student does not have access to a motion sensor? Select two answers.

vx=vx0+axt v^2x=v^2x0+2ax(x-x0)

Toy car W travels across a horizontal surface with an acceleration of aw after starting from rest. Toy car Z travels across the same surface toward car W with an acceleration of az after starting from rest. Car W is separated from car Z by a distance d. Which of the following pairs of equations could be used to determine the location on the horizontal surface where the two cars will meet, and why?

Δx=x−x0 for car W, and Δx=x−x0 for car Z. Since the location at which the cars meet represents the final position of both cars, the separation distance for both cars can be substituted into both equations to determine the final position of both cars.