Question

The next three questions pertain to the situation described below. Two blocks of mass m1 = 2 kg and m2 = 5 kg are moving toward each other along a narrow stationary frictionless track. Block 1 is initially moving to the right with speed v1 = 3 m/s and block 2 is initially moving to the left with speed v2 = 2 m/s relative to the track. After the collision, the masses move along the track. BEFORE COLLISION AFTER COLLISION v1,i v2,i v1,f v2,f m1 m2 m1 m2 17) What is the direction of the total momentum of the system of two blocks before the collision (in the track's reference frame)? to the left to the right It is zero. 18) If after the collision block 1 is moving to the left with a speed 0.5 m/s, what is the speed of block 2? |v 2,f| = 0.5 m/s |v 2,f| = 0.8 m/s |v 2,f| = 4.25 m/s |v 2,f| = 0.6 m/s |v 2,f| = 0.2 m/s 19) Imagine that the experiment is repeated but, this time, velcro is attached to the blocks so they stick and slide together on the frictionless surface after the collision. Which of the following statements about the energy of the two block system is most correct in this case? The kinetic energy of the two block system is conserved during the collision. The kinetic energy of the two block system is larger after the collision. The kinetic energy of the two block system is smaller after the collision.

          The next three questions pertain to the situation described below.

Two blocks of mass m1 = 2 kg and m2 = 5 kg are moving toward each other along a narrow stationary frictionless track. Block 1 is initially moving to the right with speed v1 = 3 m/s and block 2 is initially moving to the left with speed v2 = 2 m/s relative to the track. After the collision, the masses move along the track.

BEFORE COLLISION
AFTER COLLISION
v1,i
v2,i
v1,f
v2,f
m1
m2
m1
m2

17) What is the direction of the total momentum of the system of two blocks before the collision (in the track's reference frame)?

to the left
to the right
It is zero.

18) If after the collision block 1 is moving to the left with a speed 0.5 m/s, what is the speed of block 2?

|v 2,f| = 0.5 m/s
|v 2,f| = 0.8 m/s
|v 2,f| = 4.25 m/s
|v 2,f| = 0.6 m/s
|v 2,f| = 0.2 m/s

19) Imagine that the experiment is repeated but, this time, velcro is attached to the blocks so they stick and slide together on the frictionless surface after the collision. Which of the following statements about the energy of the two block system is most correct in this case?

The kinetic energy of the two block system is conserved during the collision.
The kinetic energy of the two block system is larger after the collision.
The kinetic energy of the two block system is smaller after the collision.

The next three questions pertain to the situation described below.

Two blocks of mass m1 = 2 kg and m2 = 5 kg are moving toward each other along a narrow stationary frictionless track. Block 1 is initially moving to the right with speed v1 = 3 m/s and block 2 is initially moving to the left with speed v2 = 2 m/s relative to the track. After the collision, the masses move along the track.

BEFORE COLLISION
AFTER COLLISION
v1,i
v2,i
v1,f
v2,f
m1
m2
m1
m2

17) What is the direction of the total momentum of the system of two blocks before the collision (in the track's reference frame)?

to the left
to the right
It is zero.

18) If after the collision block 1 is moving to the left with a speed 0.5 m/s, what is the speed of block 2?

|v 2,f| = 0.5 m/s
|v 2,f| = 0.8 m/s
|v 2,f| = 4.25 m/s
|v 2,f| = 0.6 m/s
|v 2,f| = 0.2 m/s

19) Imagine that the experiment is repeated but, this time, velcro is attached to the blocks so they stick and slide together on the frictionless surface after the collision. Which of the following statements about the energy of the two block system is most correct in this case?

The kinetic energy of the two block system is conserved during the collision.
The kinetic energy of the two block system is larger after the collision.
The kinetic energy of the two block system is smaller after the collision.

Added by Becky M.

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