A ball has a mass of 0.5kg. dropped from a cliff top, the ball hits the sea below at a speed of 10./s.
a) what is the kinetic energy of the ball as it is about to hit the sea?
b) What was the ball's gravitational potential energy before it was dropped?
c) from what height was the ball dropped?
d) a stone of mass 1kg also hits the sea at 10m/s.