An arrow is fired directly horizontal off a cliff that is 10.0 meters tall with a velocity of 65.5m/s. How long is the arrow in the air? *

Arailroad car collides with and sticks to an identical railroad car that is initially at rest. after the collision, the total kinetic energy of the two cars is a) the same as before. b) half as much as before. c) one third as much as before. d) one fourth as much as before. e) twice as much as before.