An astronaut on a planet with no atmosphere drops a feather into a 7.17m deep crater and records that the feather falls freely for 1.61s. What is magnitude of free-fall acceleration on the planet?

This energy transformation diagram represents the energy of a skateboarder moving along a half-pipe. as she skates toward the top of the half-pipe, her original kinetic energy is converted to potential energy and friction. how much of the energy is potential?