The spot marked “maximum gravitational potential energy” should be on the lowest point of the roller coaster, at the far left side on the bottom.

Answer 1

This is because gravitational potential energy is highest at the highest point of the roller coaster, and decreases as the roller coaster moves towards the ground. At the lowest point of the roller coaster, the potential energy is at its minimum as the coaster is closest to the ground and has the least amount of potential energy.