AP Physics 1 Momentum

Two carts, of mass 2m and m, approach each other head-on with the same speed v, as shown in the figure above. When the carts collide, they hook together. Assuming positive momentum is to the right, which of the following best represents the momentum of the cart of mass m as a function of time before and after the collision?

---------------- | | -------|

The graph above shows the position x as a function of time for the center of mass of a system of particles of total mass 6.0 kg. For a very short time interval around 2.0 s, an external force is exerted on an object in the system. What is the resulting change in momentum of the system?

-18 kg•m/s

Object X travels across a horizontal surface and collides with object Y. The velocity as a function of time for object X and object Y before, during, and after the collision is shown in the graph. Both objects have a mass of 2kg. Which of the following correctly describes the momentum p⃗ of the system and the kinetic energy K of the system?

-> p K conserved not conserved

A person applies an impulse of 5.0 kg∙m/s to a box in order to set it in motion. If the person is in contact with the box for 0.25 s, what is the average force exerted by the person on the box?

20.0 N

The student conducts a second experiment in which the magnitude of the force exerted on block X from block Y is measured over the time in which the collision takes place. A graph of the force as a function of time is shown. In a third experiment, the student creates a collision such that the force exerted on block X from block Y is constant for 0.020 s. Which of the following constant forces, if exerted on block X from block Y, would produce the same change in momentum as is shown by the graph?

200 N

A student performs an experiment in which two blocks, block X of mass 2kg and block Y of mass 3kg, are tied together by a rope. The system containing Block X and Block Y is dropped above Earth's surface in the orientation shown in Figure 1. A motion detector below each block collected data that were graphed to show the velocity as a function of time for Blocks X and Y as they fell toward the ground. The graphs are shown in Figure 2 and Figure 3, respectively. The positive direction is considered to be down. The change in momentum for the system containing block X and block Y is most nearly

250 kg⋅m/s

Block X of mass 2kg and block Y of unknown mass travel toward each other. An elastic collision occurs in which momentum is conserved. The graph shows the velocity of block X and of velocity of block Y as a function of time before, during, and after the collision. What is the mass of block Y?

6kg

A cart of mass 1kg travels along a horizontal, frictionless surface. A net force is applied to the cart. A graph of the net force applied to the cart as a function of time is shown. The initial and final direction of the cart and the direction of the net force exerted on the cart is unknown. The distance of one grid unit represents a change in velocity of 1 ms. Which of the following diagrams could represent the direction and relative magnitude of the velocity of the cart before the force is applied and after the force is applied? Select two answers.

A. before after <- ---------> D. before after -> -------------->

Cart X of mass m0 travels along a horizontal surface with a constant speed in the positive horizontal direction. Cart X then collides with cart Y of mass M0, which was initially at rest. After the collision, cart Y has a positive velocity. Immediately after the collision, cart X and cart Y could have one of three final velocities that are indicated in the table. In all scenarios, the total momentum of the two-cart system is the same before and after the collision.

Graphs II and IIIIII only

A ball is dropped and bounces off the floor. Its speed is the same immediately before and immediately after the collision. How does the height to which the ball bounces compare to the height from which it was dropped?

It is the same.

A 2 kg object traveling at 5 m/s on a frictionless horizontal surface collides head-on with and sticks to a 3 kg object initially at rest. Which of the following correctly identifies the change in total kinetic energy and the resulting speed of the objects after the collision?

Kinetic Energy Speed decreases 2 m/s

A ball is dropped and bounces off the floor. Its speed is the same immediately before and immediately after the collision. Which of the following is true about the collision between the ball and the floor?

The ball's momentum changes direction but not magnitude.

Object X of mass m0 travels to the right with a velocity v0. Object Y of mass 2m0 moves to the left at 2v0, as shown in the figure. The objects collide and then stick together. What is the change in kinetic energy of the two-object system from immediately before the collision to immediately after the collision?

The kinetic energy decreases by 3m0v^20

A student plans to conduct an experiment in which the momentum of a two-object system can be determined immediately before and after a collision takes place. The student slides block X at an unknown constant speed toward an identical block, block Y, that is initially at rest, as shown in the figure. There is negligible friction between the blocks and the surface. The student uses the data collected from the experiment to create the data table. Which of the following statements is true regarding the data?

The momentum of the two-block system is not conserved because the initial momentum of the system is not equal to the final momentum of the system.

Two identical spaceships are traveling in deep space, far from any planets or stars. The ships travel in the same direction, with the slower one directly behind the faster one. The ships are connected by a cable attached to a spool, so that the part of the cable outside the ships can be made longer or shorter as needed. The cable is used to bring the ships to the same speed for a transfer of cargo. The graph above shows the speed of the two ships during a 10 s interval. Does at least one of the ships have its engine turned on during the time interval shown, and what evidence indicates so?

Yes, because the momentum of the two-rocket system increases.