1. The problem statement, all variables and given/known data What is the gravitational potential energy of a car with centre of mass at a height h above the ground? On a level road the centre of mass is at a height of 0.1m above the ground. 2. Relevant equations gravitational potential energy=mgh 3. The attempt at a solution I would use the formula mgh to calculate the gravitational potential energy of the car. However, the book gives mg(h-0.1) as the answer. I am not convinced because I think the definition of gravitational potential energy is related to the position of the centre of mass above the ground, not its change of gravitational energy before and after. Am I correct?