#2: A 5 kg cannonball is fired from the ground straight up into the air such that it rises to a
height of 50 m.
a) What is the potential energy of the cannonball when it gets to its maximum height?
b) What is the speed of the cannonball just before it falls back to the ground? Note that if we
ignore air friction, this is the same as the
initial speed of the cannonball when it was fired from
the cannon.