Final answer:
The skateboarder has the most potential energy at the top of the ramp due to her maximum height above the reference point. As she descends, the potential energy is converted to kinetic energy, reaching its minimum at the bottom of the ramp.
Step-by-step explanation:
The skateboarder at the half pipe has the most potential energy at the top of the ramp. This is due to gravitational potential energy, which depends on the height of an object above a reference point. When the skateboarder is at the top of the ramp, her height is at its maximum, and therefore her potential energy is also at its maximum. As she moves down the ramp to the bottom, this potential energy is converted into kinetic energy, which is the energy of motion. At the bottom of the ramp, the potential energy is at its minimum because her height above the reference point (the bottom of the ramp) is the lowest. As she moves back up the other side, her potential energy increases again as her height increases, but until she reaches a point equally as high as the starting point, her potential energy remains less than it was at the top of the first side.
The law of conservation of energy states that the total mechanical energy (potential plus kinetic) in a closed system without energy loss to friction remains constant. Therefore, at the bottom of the ramp, while potential energy is minimal, kinetic energy is at its maximum. Conversely, at the top of the ramp, potential energy reaches its maximum value while kinetic energy is minimal or zero if she is momentarily stationary at that point.