The answer is 117.6 J
The potential energy of
the object is actually its stored energy:
E =
m · g · h
E - the potential energy of the object,
m - the mass of the object,
g - acceleration due to gravity,
h - the height of the object.
m = 4 kg
g = 9.8 m/s²
h = 3 m
E = 4 * 9.8 * 3 = 117.6 J