Take into account that the potential energy is given by the following formula:
U = m·g·h
where
m: mass = 80 kg
g: gravitational acceleration constant = 9.8m/s²
h: height = 7 m
Replace the previous values into the expression for the potential energy U:
U = (80 kg)(9.8 m/s²)(7 m)
U = 5,488 J
Hence, Bobby will have a potential enrgy of 5,844 J when he is a the top of a 7 m hill.
