Question

The diagram shows a side view of a skateboard ramp.

An illustration of a skateboarding halfpipe from the end. The top of the curve on the left is labeled W, the top of the curve of the right is labeled Z, part of the way down the curve on the left is labeled X and part of the way down the curve on the right is labeled Y.

At which labeled points would the skateboarder have the most kinetic energy?

W and X
X and Y
Y and Z
W and Z

Answer 1

X and Y.

By energy conservation (ignoring friction), gravitational potential energy is converted to kinetic energy as the skateboarder goes down. The lower points (X and Y) are at smaller height than the tops (W and Z), so the skateboarder has more kinetic energy at X and Y.