Gravitational potential energy = (mass) x (gravity) x (height)
-- For the ball: PE = (2) x (9.8) x (2.2) = 43.12 joules
-- For the bullet: PE = (0.15) x (9.8) x (74) = 108.78 joules
Relative to the ground, the bullet has more gravitational potential energy than
the ball has, because it is 33.6 times as high off the ground as the ball is.
Where it got all of that gravitational potential energy is either somebody
carried it up a bunch of stairs from the ground to the height of 74 meters,
or else the charge of gunpowder in the shell exploded, releasing a bunch
of chemical energy, and flinging the bullet up to that great height.
