A 25 kg child is bouncing on a trampoline, which can be treated as an ideal spring with spring constant 2900 N/m. If the trampoline compresses to a maximum of 0.38 m during the bouncing, what is the maximum height that she reaches above the uncompressed surface of the trampoline? You may ignore friction.

Explanation:

Energy store in the compressed trampoline = potential energy of at the maximum height ignoring friction

energy stored in the trampoline = where k is spring constant and x is the distance compressed  = 0.5 × 2900 × 0.38² = 209.38 J

209.38 J = 25 × 9.8 × h

h maximum height attain = 209.38 J / ( 25 × 9.8) = 0.855 m