In the context of gravitational potential energy, where is the potential energy of a roller coaster the lowest?

Which two types of potential energy are considered forms of mechanical energy?

What is the gravitational potential energy of a $1\mathrm{kg}$ ball that is $2m$ above the floor? (Assume $g=9.8m/s^2$)

If a $2\mathrm{kg}$ rock has $196J$ of gravitational potential energy near Earth's surface, what is its height above the ground? (Assume $g=9.8m/s^2$)

At which point on a roller coaster would a car have the greatest $gravitationalpotentialenergy$?

At which position on a hill does a car have the greatest $U=mgh$ (gravitational potential energy)?

Which of the following best explains how gravitational potential energy was added to the water in a typical hydroelectric dam setup?

When skiing downhill, what type of potential energy do skiers primarily take advantage of?