PPC UNIT 5 A AND

Astronaut XX of mass 50kg50kg floats next to Astronaut YY of mass 100kg100kg while in space, as shown in the figure. The positive direction is shown. Astronaut XX applies a force against Astronaut YY such that the kinetic energy of each astronaut as a function of time is shown in the graph. What is the change in momentum of the two-astronaut system and the change in momentum of each astronaut from immediately before the force was applied to immediately after the force was applied?

0, -100, 100

Block XX and block YY travel toward each other along a horizontal surface with block XX traveling in the positive direction. Block XX has a mass of 4kg4kg and a speed of 2ms2ms. Block YY has a mass of 1kg1kg and a speed of 1 ms1 ms. A completely inelastic collision occurs in which momentum is conserved. What is the approximate speed of block XX after the collision?

1.4

A 9000kg9000kg rock slides on a horizontal surface with negligible friction at 3m/s3m/s toward a 3000kg3000kg rock that is at rest, as shown in Figure 1. A collision occurs such that the two rocks remain stuck together and travel with a common final speed vfvf , as shown in Figure 2. What is the speed vfvf of the two-object system after the collision?

2.25

A force is applied to a 2kg2kg object, and measurements of the force as a function of time are shown. The force is the only force exerted on the object and is applied in the direction of the object's velocity. Which of the following could represent the initial velocity, v0v0, and the final velocity, vfvf, of the object?

4,6

Block XX and block YY travel toward each other along a horizontal surface with block XX traveling in the positive direction. Block XX has a mass of 2kg2kg and a speed of 3m/s3m/s. Block YY has a mass of 1kg1kg and a speed of 3m/s3m/s. After the collision, block XX travels in the horizontal direction with a speed of 1m/s1m/s in the negative direction. What is the speed of block YY if the collision is elastic?

5m/s

Block XX of mass MM slides across a horizontal surface where friction is negligible. Block XX collides with block YY of mass 2M2M that is initially at rest, as shown in Figure 1. After the collision, both blocks slide together with a speed vsvs , as shown in Figure 2. What is the kinetic energy of the two-block system before the collision?

9/2

A student performs several experiments in which two carts collide as they travel along a horizontal surface. Cart XX and Cart YY both have a mass of 1kg1kg. Data collected from the three experiments are shown in the table. During which experiment does the center of mass of the system of two carts have the greatest change in its momentum?

All experiments have the same change in momentum for the center of mass of the system of two carts.

Block XX of mass MM slides across a horizontal surface where friction is negligible. Block XX collides with block YY of mass 2M2M that is initially at rest, as shown in Figure 1. After the collision, both blocks slide together with a speed vsvs , 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

Two objects of the same mass travel in opposite directions along a horizontal surface. Object X has a speed of 5ms and object Y has a speed of 5ms, as shown in the figure. After a period of time, object X collides with object Y. In scenario 1, the objects stick together after the collision. In scenario 2, the objects do not stick together after the collision.

By determining the area bound by the curve and the horizontal axis from 0s0s to 0.01s0.01s

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 of the experiments indicate the presence of a net external force.

A student conducts an experiment in which a cart is pulled by a variable applied force during a 2 s2 s time interval. In trial 1, the student exerts the force on a cart of mass MM. In trial 2, the student exerts the force on a cart of mass 3M3M. In trial 3, the student exerts the force on a cart of 5M5M. In which trial will the cart experience the greatest change in momentum from 0 s0 s to 2 s2 s?

The change in momentum is equal for all three trials from 0 s0 s to 2 s2 s.

A student conducts an experiment to verify whether momentum is conserved for a situation in which a collision occurs. The two objects, Object XX and Object YY, 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 YY immediately after the collision is greater than the kinetic energy of block XX immediately after the collision.

Two objects of the same mass travel in opposite directions along a horizontal surface. Object X has a speed of 5ms and object Y has a speed of 5ms, as shown in the figure. After a period of time, object X collides with object Y. In scenario 1, the objects stick together after the collision. In scenario 2, the objects do not stick together after the collision. Which of the following claims is true regarding how the outcome of scenario 1 is different from the outcome of scenario 2?

The kinetic energy of the system in scenario 1 will be less than that in scenario 2 after the collision.

An experiment is conducted in which a cart travels across a horizontal surface and collides with a wall. Data collected from the experiment are used to create the graph of the cart's velocity as a function of time. All frictional forces are considered to be negligible. Which data from the graph should the student use to determine the direction of the net force exerted on the cart and the direction of the change in momentum of the cart from the time intervals of A to B?

The slope of the line from AA to BB, because that will provide information about the acceleration of the cart.

Block XX of mass MM slides across a horizontal surface where friction is negligible. Block XX collides with block YY of mass 2M2M that is initially at rest, as shown in Figure 1. After the collision, both blocks slide together with a speed vsvs , as shown in Figure 2. What is the speed of the center of mass of the two-block system immediately before the collision?

The speed is vsvs.

A toy car of mass 2kg2kg travels along a horizontal surface with negligible friction at a speed of 1.0ms1.0ms. The car then collides with a vertical wall. The wall applies a force of magnitude 20N20N for 0.2s0.2s on the toy car. Which of the following predicts the motion of the toy car immediately after the collision?

The speed of the car will remain the same, and the car will travel in the opposite direction.

Block XX and block YY are tied together by a rope. The system containing block XX and block YY is released from rest on a ramp, as shown in the figure. Block YY has a smaller mass than block XX. Which of the following claims is correct regarding the momentum of the system containing only block XX and the system that contains block XX and block YY?

The system containing block XX is an open system, and the system of both blocks is an open system.

A mass M1M1 slides along a horizontal surface and collides with and sticks to a mass M2M2 that is initially at rest at the bottom of a ramp, as shown in Figure 1. Frictional forces between the masses, the surface, and the ramp are considered to be negligible. After the collision, masses M1M1 and M2M2 slide together up the curved ramp as a total mass of M12M12 , as shown in Figure 2. The two masses eventually come to rest at their highest position along the ramp. Which of the following claims is correct regarding the momentum of the system of mass M1M1 and the system of mass M1M1 and M2M2 in terms of their momenta?

The system of mass M1M1 is an open system, and the system of mass M1M1 and M2M2 is an open system.

n an experiment, two objects, Object XX and Object YY, 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 XX and Object YY 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.

A cart is attached to a hanging block by a string that passes over a pulley, as shown in the figure. The pulley has negligible friction in its axle and negligible mass. A student must determine the change in momentum of the cart as it is pulled across the horizontal surface from the moment the cart is released from rest to the moment immediately before the cart collides with the pulley. Which of the following lists the measuring devices that are needed to determine the change in momentum of the cart?

Timer, mass balance, and meterstick

During an experiment, a toy car accelerates forward for a total time of 5s5s. Which of the following procedures could a student use to determine the average net force exerted on the car during the 5s5s that the car accelerates?

Use a balance to determine the mass of the car. Use a motion sensor to measure the speed of the car at a time of 0s0s and a time of 5s5s.

Cart XX travels in the positive direction along a horizontal surface, and cart YY 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

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 XX travels towards Block YY that is initially at rest, as shown in the figure, and eventually collides with Block YY. Which of the following diagrams represents the final velocities for Block XX and Block YY after the collision if the collision is elastic?

arrow at the end is 6.4

A student must conduct an experiment to verify the conservation of momentum. Cart XX and Cart YY 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?

arrows in the middle

Two objects of the same mass travel in opposite directions along a horizontal surface. Object X has a speed of 5ms and object Y has a speed of 5ms, as shown in the figure. After a period of time, object X collides with object Y. In scenario 1, the objects stick together after the collision. In scenario 2, the objects do not stick together after the collision. Consider scenario 1. Is the object X-object Y system open or closed? Predict whether both the momentum and the kinetic energy of the system will be the same or different after the collision.

closed, same, changes

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.

coefficents of 3 and 7

A block of mass of 10kg10kg travels in the positive direction along a surface with negligible friction. The block has an initial momentum 18kg⋅ms18kg⋅ms. The block collides with an object of an unknown mass that is at rest. The force exerted on the block as a function of time is shown on the graph. Which of the following best predicts the speed and direction of the block immediately after the collision?

decreases, same direction

Cart XX with a mass of 1kg1kg 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 XX collides with cart YY, which is initially at rest. The collision is completely inelastic, and both cart XX and cart YY have equal masses. Before and after the collision, data are collected about the distance dd each cart travels as a function of time tt. The table shows data about cart XX before the collision as it travels down the ramp. Which of the following sets of data could represent the collision for cart XX and cart YY?

last number, third column, 6.1

Block XX of mass MM travels with a speed v0v0. Block YY of mass 2M2M travels with a speed 2v02v0. 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 vfvf 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 student must conduct an experiment in which an elastic collision occurs. In the experiment, Block XX of mass 2kg2kg travels with a velocity vXvX in the positive direction toward Block YY of mass 2kg2kg that is at rest, as shown in Figure 1. After the collision, Block YY travels in the positive direction with velocity vYvY while Block XX 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 XX and Block YY open or closed?

no, open

A block travels across a horizontal surface in which frictional forces are not considered to be negligible, as shown in the figure. Which of the following quantities should a student measure to verify that the direction of the frictional force exerted on the block from the surface is in the same direction as the change in momentum of the block? Select two answers. Justify your selections.

the final velocity, the initial velocity

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.

triangle PZ / FA