Question

Olivia is on a swing at the playground.

A girl is swinging on a swing set. At W she is about 45 degrees up and to the left. At X she is near the bottom of the swing just to the left. At Y she is near the bottom of the swing just to the right. At Z she is about 45 degrees up and to the right.
If the swing is moving from W to Z, at which point is her kinetic energy increasing and her potential energy decreasing? (based on a starting point of W)

W
X
Y
Z

Answer 1

X

Explanation: starting at W she’s descending toward the bottom. As height decreases, gravitational potential energy falls and that lost potential is converted into kinetic energy, so KE increases during the descent (e.g., at X). After the lowest point (past X toward Y and Z) KE begins to decrease and PE increases.