Two balls are placed, one above the other, and dropped from a
height of 1.4 m. The bottom ball has a mass which is 10 times the
mass of the top ball. They are dropped from rest. When the balls
strike the floor, they have a head on, elastic collision with one
another. (Assume that the bottom ball strikes the floor, instantly
reverses direction, and then collides with the top ball, which is
still travelling downward.) How high will the...