A 42 kg girl is bouncing on a trampoline. During a certain interval after she leaves the

Question

surface of the trampoline, her kinetic energy decreases to 250 J from 520 J. How high
does she rise during this interval?

Answer 1

KE+PE = 520 J.
250 + PE = 520
PE = 520-250 = 270 J.
mg*h = 270
h = 270/m*g = 270/(42*9.8) = 0.656 m.