AP Physics Practice Exam 1

A rubber ball with mass .20 kg is dropped vertically from a height of 1.5 m above a floor. The ball bounces off the floor, and during the bounce 0.60 J of energy is dissipated. What is the maximum height of the ball after the bounce?

1.2 m

A block of mass 2.0 kg, starting from rest, is pushed with a constant force across a horizontal track. The position of the block as a function of the time is recorded, and the data are shown in the table. What is the magnitude of the change in momentum of the block between zero and 4.0 seconds?

1.6 kg•m/s

An object is moving to the west at a constant speed. Three forces are exerted on the object. One force is 10 N directed due north, and another is 10 N directed due west. What is the magnitude and direction of the third force if the object is to continue moving to the west at a constant speed?

10√2 N, directed southeast

The total distance by the object between 0.35 s and 0.40 s is most nearly

2 cm

The frequency of oscillation is most nearly

2.0 Hz

Block A of mass 2.0 kg is released from rest at the top of a 3.6 m long plane inclined at an angle of 30°, as shown in the figure above. After sliding on the horizontal surface, block A hits and sticks to block B, which is at rest and has mass 3.0 kg. Assume friction is negligible. The speed of the blocks after the collision is most nearly

2.4 m/s

The wheel on a vehicle has a rotational inertia of 2.0 kg•m². At the instant the wheel has a counterclockwise angular velocity of 6.0 rad/s, an average counterclockwise torque of 5.0 N • m is applied, and continues for 4.0 s. What is the change in angular momentum of the wheel?

20 kg • m² / s

A 12kg box sliding on a horizontal floor has an initial speed of 4m/s. The coefficient of friction between the box and the floor is 0.20. The box moves distance of 4.0 m in 2.0 s. The magnitude of the change in momentum of the box during this time is most nearly... A) 12 kg/m B) 48 kg/m C) 60 kg/m D) 96 kg/m

48 kgm

Carts 1 and 2 are initially moving toward each other, as shown in the top figure. The carts collide and afterward are both moving to the right, as shown in the bottom figure. If the positive direction is to the right, which of the following best represents the force exerted on each cart by the other during collision as a function of time?

A

A cart is moving on a level track in the positive x-direction. A force acting parallel to the x-axis is exerted on the cart. The graph above shows the net force exerted on the cart as a function of displacement. As the cart travels from x =0 m to x = 4 m, what is the net change in the kinetic energy of the cart?

An increase of 10 J

A projectile fired into the air explodes and splits into two halves of equal mass that hit the ground at the same time. If the projectile had not exploded, it would have landed at point X, which is a distance R to the right of the launch point. After the explosion, one of the halves lands at point Y, which is a distance 2R to the right of the launch point. If air resistance is negligible, where did the other half land?

At the launch point

A student uses a spring scale to exert a horizontal force on a block, pulling the block over a smooth floor. The student repeats the procedure several times, each time pulling the block from rest through a distance of 1.0 m. For which of the following graphs of force as a function of distance will the block be moving the fastest at the end of the 1.0m ?

B

Block A is set on a rough horizontal table and it connected to a horizontal spring that is fixed to a wall, as shown. Block A is then also connected to hanging block B by a lightweight string that passes over an ideal pulley, as shown. The friction force exerted on block A by the table is not negligible. The blocks are initially held at rest so that the spring is not stretched. When the blocks are released, hanging block B moves downward and block A on the table moves to the right until the system comes again to rest. Let E1 be the mechanical energy of the blocks-spring system, and let E2 be the mechanical energy of the blocks-spring-Earth system. How do these two energies change from when the blocks are held at rest to when the blocks come to rest again?

Blocks-Spring System: Increases Blocks-Springs-Earth System: Decreases

The figures show a cart moving over the top of a hill (Case 1), moving at the bottom of a dip (Case 2), and moving at the top of a vertical loop (Case 3). In each case, the normal force acting on the car is Fn and the weight of the car is Fg. In which case is it always true that Fn> Fg, and in which case is it always true that Fn< Fg?

Case 2: Fn > Fg Always Case 1: Fn < Fg Always

An elevator carrying a person of mass m is moving upward and slowing down. How does the magnitude F of the force exerted on the person by the elevator floor compare with the magnitude mg of the gravitational force?

F > mg

A student is asked to move a box from ground level to the top of a loading dock platform, as shown in the figures above. In Figure 1, the student pushes the box up an incline with negligible friction. In Figure 2, the student lifts the box straight up from the ground level to the loading dock platform. In which case does the student do more work on the box, and why?

Neither method, because the work is the same in both cases, since using the ramp decreases the force by the same factor that it increases the distance.

A blue sphere and a red sphere with the same diameter are released from rest at the top of a ramp. The red sphere takes a longer time to reach the bottom of the ramp. The spheres are then rolled off a horizontal table at the same time with the same speed and fall freely to the floor. Which sphere reaches the floor first?

Neither; the spheres reach the floor at the same time.

A soft foam block of mass m slides without friction in the positive x-direction with speed v. At the time t = 0, a student briefly pushes the block with a force probe in the positive x-direction. The graph above shows the force probe's measurements as a function of time during the push. Which of the following statements is true about the block's momentum between t = 0 and t = t1

The momentum of the block has increased by approximately 1/2 F0t1.

The motion of an object is shown in the velocity-time graph. Which best describes the motion of the object?

The object travels in the same direction for the entire time.

The speed of the object at time t = .65 s is most nearly equal to which of the following?

The slope of the tangent to a best-fit sinusoidal curve at .65 s.

A sled slides down a hill with friction between the sled and hill but negligible air resistance. Which of the following must be correct about the resulting change in energy of the sled-Earth system?

The sum of the kinetic energy and the gravitational potential energy changes by an amount equal to the energy dissipated by friction.