AP Physics 1 Unit 5 Progress Check B

Block X and block Y travel toward each other along a horizontal surface with block X traveling in the positive direction. Block X has a mass of 4kg and a speed of 2ms. Block Y has a mass of 1kg and a speed of 1 ms. A completely inelastic collision occurs in which momentum is conserved. What is the approximate speed of block X after the collision?

1.4 m/s

An object travels in the positive direction with a momentum of 5 kg⋅ms . An applied force is exerted on the object, and a graph of the magnitude of the applied force as a function of time is shown. All frictional forces are considered to be negligible. Which of the following could represent the approximate momentum of the object after the force has been applied? Select two answers.

3 and 7

Block X of mass M slides across a horizontal surface where friction is negligible. Block X collides with block Y of mass 2M that is initially at rest, as shown in Figure 1. After the collision, both blocks slide together with a speed vs , as shown in Figure 2. What is the kinetic energy of the two-block system before the collision?

3/2 Mv2s

Block X and block Y travel toward each other along a horizontal surface with block X traveling in the positive direction. Block X has a mass of 2kg and a speed of 3m/s. Block Y has a mass of 1kg and a speed of 3m/s. After the collision, block X travels in the horizontal direction with a speed of 1m/s in the negative direction. What is the speed of block Y if the collision is elastic?

5 m/s

A student must perform an experiment in which two objects travel toward each other and collide so that the data collected can be used to show that the collision is elastic within the acceptable range of experimental uncertainty. Which of the following measuring tools, when used together, can the student use to verify that the collision is elastic? Select two answers.

A motion detector, a balance

Block X of mass M slides across a horizontal surface where friction is negligible. Block X collides with block Y of mass 2M that is initially at rest, as shown in Figure 1. After the collision, both blocks slide together with a speed vs , as shown in Figure 2. How could a student verify that the collision under consideration is an inelastic collision for the two-block system?

By comparing the final kinetic energy of the system with the initial kinetic energy of the system

A student must conduct an experiment to verify the conservation of momentum. Cart X and Cart Y travel toward each other and eventually collide, as shown in the figure. The student has access to the two carts, one mass balance, and two motion detectors. If the mass of each cart is known, how should the student arrange one or both motion detectors so that the student can collect enough information about the motion of the carts, in order to verify the conservation of momentum of the system?

Correct. To verify the conservation of momentum, the momentum of the system before the collision should be the same as the momentum of the system after the collision. Therefore, a student must measure the initial velocities of Cart XX and Cart YY and the final velocities of Cart XX and Cart YY. This combination of motion detectors and their positions will allow for the velocities of each object to be measured before, during, and after the collision. (two sensors on the outsides)

A student must conduct an experiment in which an elastic collision occurs. In the experiment, Block X of mass 2kg travels with a velocity vX in the positive direction toward Block Y of mass 2kg that is at rest, as shown in Figure 1. After the collision, Block Y travels in the positive direction with velocity vY while Block X remains nearly at rest. Data collected of the initial and final velocities of both blocks for three trials of the experiment are shown in the table. Did the student conduct an experiment in which an elastic collision occurred? Is the system of Block X and Block Y open or closed?

Elastic? no. Open? heck yeah.

A student conducts three experiments in which two carts, cart 1 and cart 2, travel toward each other and collide. A graph of each cart's momentum as a function of time is shown above. In which experiment, if any, does the graph indicate the presence of a net external force exerted on the two-cart system?

None

A student conducts an experiment to verify whether momentum is conserved for a situation in which a collision occurs. The two objects, Object X and Object Y, travel toward each other, as shown in Figure 1. After the collision, the two objects travel as shown in Figure 2. Data collected from three trials of this experiment are shown in the table. Which of the following statements is correct based on the data?

The conservation of momentum can be verified within the threshold of experimental uncertainty.

Block X of mass 2kg travels across a horizontal surface toward block Y of unknown mass that is initially at rest. Block X then collides elastically with block Y. A graph of the position as a function of time for block X is shown. Block X and block Y are made of the same material. Which of the following predictions is correct about the motion of block Y immediately after the collision?

The kinetic energy of block Y immediately after the collision is greater than the kinetic energy of block X immediately after the collision.

In an experiment, two objects, Object X and Object Y, travel toward each other and collide. Data are collected about each object before, during, and after the collision to create a graph that shows the momenta of Object X and Object Y as a function of time. How should a student use the data found on the graph to verify the conservation of momentum?

The vector sum of the momenta should be compared, because momentum is a vector quantity.

A variable applied force is exerted on a 2kg block as it travels across a horizontal surface for a time of 2s, as shown in the graph. Before the force is applied to the block, it travels with a speed of 1 ms. The force is exerted on the block in the same direction as the block's displacement while the force is exerted. After the force is applied to the block, the block travels with a speed of 5 ms. Which of the following statements are correct regarding the motion of the block? Select two answers.

There must be another force exerted on the block during the time in which the applied force is exerted. The change in momentum of the block from the applied force is 5 kg⋅ms5 kg·ms.

Cart X travels in the positive direction along a horizontal surface, and cart Y travels in the positive direction. The carts collide, and a student collects data about the carts' velocities as a function of time before, during, and after a collision, as shown. The masses of both objects are known. Which of the following best indicates how the student should use the graph to determine whether the collision is elastic or inelastic and provides a correct justification?

Using the known mass and known velocity for each cart to determine the kinetic energy of the system before and after the collision, because the kinetic energy changes in an inelastic collision

Cart X with a mass of 1kg is released from rest at the top of an inclined ramp, and the cart rolls down the ramp with negligible friction. At the bottom of the ramp, cart X collides with cart Y, which is initially at rest. The collision is completely inelastic, and both cart X and cart Y have equal masses. Before and after the collision, data are collected about the distance d each cart travels as a function of time t. The table shows data about cart X before the collision as it travels down the ramp. Which of the following sets of data could represent the collision for cart X and cart Y?

dm- 12 14 16 etc

Block X of mass M travels with a speed v0. Block Y of mass 2M travels with a speed 2v0. Both blocks travel toward each other and collide. After the blocks collide, they separate so that the kinetic energy of the system remains conserved. Which of the following equations for the conservation of momentum could a student use to help determine the speed vf of each block after the collision?

m0v0−4m0v0=m0vXf+2m0vYfm0v0−4m0v0=m0vXf+2m0vYf, because the two blocks initially travel in opposite directions, and the blocks do not stick after the collision.

A constant force FA is applied to an object of mass M, initially at rest. The object moves in the horizontal x-direction, and the force is applied in the same direction. After the force has been applied, the object has a speed of vf. Which mathematical routines can be used to determine the time in which the force is applied to the object of mass M? Select two answers.

t=Δpx/FA Δt=Mvf/FA

Block X of mass M slides across a horizontal surface where friction is negligible. Block X collides with block Y of mass 2M that is initially at rest, as shown in Figure 1. After the collision, both blocks slide together with a speed vs , as shown in Figure 2. What is the speed of the center of mass of the two-block system immediately before the collision?

v