What is the wave called the one that: A wave in which the motion of the medium is in the same direction as the wave. Put simply, when a wave moves forward and back.

You throw a ball upward and let it fall to the ground. your friend drops an identical ball straight down to the ground from the same height. is the change in kinetic energy (from just after the ball is released until just before it hits the ground) of your ball greater than, less than, or equal to the change in kinetic energy of your friend's ball?