Potential energy is the energy possessed by a body at rest while the kinetic energy is the energy possessed by a body in motion.
Potential energy is given by mass× gravitational acceleration × height
That is energy = mgh
For the first ball the potential energy is 2.268 ×10 ×5 = 113.4 J (5 lb = 2.268 kg)
The second ball with the same mass will have 2.268 ×10 ×10 = 226.8 J
Thus, the potential energy is dependent on the height of a given body and therefore the ball at the 5 foot hill has less potential energy.