
If the big truck and the smaller truck have equal momentum, as stated in the equal momentum example, then the smaller truck will have to have a higher velocity. Since kinetic energy depends upon the square of the velocity, this implies that the smaller truck will have a higher kinetic energy. By the workenergy principle, then, it will take more work to stop the smaller truck.
If the trucks were traveling at the same speed, it would of course take more work to stop the bigger truck.
