An object of mass 1.5 kg rests on a shelf where it has a gravitational potential energy of 7 joules. An object of mass 4.5 kg is placed on the same shelf. What is the gravitational potential energy of this second object?

Answer 1

Pe1 = 1.5 * g * h
Pe2 = 4.5 * g * h

so Pe2 = (4.5/1.5) (7)