The figure below shows the experimental setup to study the collision between two carts.

Question

In the experiment cart A rolls to the right on the level track, away from the motion sensor at the left end of the track. Cart B is initially at rest. The mass of cart A is equal to the mass of cart B. Suppose the two carts stick together after the collision. Assume the carts move frictionlessly.

The kinetic energy of the two carts after the collision

1)is equal to one half the kinetic energy of cart A before the collision.
2)is equal to one quarter the kinetic energy of cart A before the collision.
3)is equal to the kinetic energy of cart A before the collision.
4)is equal to twice the kinetic energy of cart A before the collision.
5)is equal to four times the kinetic energy of cart A before the collision.
6)None of the above.

Answer 1

mv=(2m)u
u=v/2
KE(of two carts) =(2m)u²/2=mv²/4 =0.5(mv²/2) =0.5KE(cart A)
Ans 1)