If he does this 29 times, how much work has he done? Answer in units of J.

Question

A cheerleader lifts his 36.7 kg partner straight up off the ground a distance of 0.698 m before releasing her. Assume the partner’s velocity is zero at the beginning and the end of the lift. The acceleration of gravity is 9.8 m/s 2 . If he does this 29 times, how much work has he done? Answer in units of J.

Answer 1

"...Assume the partner’s velocity is zero at the beginning and the end of the lift..m" is the key here. The cheerleader does at each lift TWICE the work: first he'd accelerate his partner but then he'd slow him down to zero speed. So on each lift he'd do the work 2mgh. Multiply then by 29, that's all

Best,

Dr.Ariel B