Pushing a Cart 2

Consider two carts, of masses m and 2m, at rest on an air track. If you push first one cart for a certain amount of time and then the other for the same length of time, exerting equal force on each, the kinetic energy of the light cart is

A) four times the kinetic energy of the heavy cart.

B) twice the kinetic energy of the heavy cart.

C) equal to the kinetic energy of the heavy cart.

D) half the kinetic energy of the heavy cart.