The change in potential energy of this monkey is going to be equal to ‘mgh’. That’s our formula for gravitational potential energy change. ‘Mg’ times the height difference. So the mass is seven kilograms times 9.8 Newtons per kilogram times 1.2 meters that the monkey goes up and that’s ANSWER Joules. In the fifth edition you have 6.0 kilograms here instead of seven. Otherwise the same and the fifth edition answer is ANSWER Joules.