Hi there!
We can use the following:
U (Gravitational Potential Energy) = mgh
m = mass of object (kg)
g = acceleration due to gravity OR gravitational field strength
h = height, or displacement (m)
ΔU = Uf - Ui, so:
Uf = 3 × 1.5 × 10 = 45 J
Ui = 3 × 0 × 10 = 0
ΔU = Uf - Ui = 45 - 0 = 45 J
