The potential energy of an object is defined as the energy it harnesses as a result of the downwards pull of gravity. The acceleration due to gravity is equivalent to 9.8 m/s^2. Potential energy can be calculated using the formula: PE = mgz
where:
m = mass
g = acceleration due to gravity
z = height
Therefore, for this problem, the PE = 70(9.8)(8) = 5488 Joules