How long would a 150 W lightbulb have to glow to produce the same amount of energy expended by Georgie? Answer in units of s.

Question

Georgie was pulling her brother (of mass 28 kg) in a 9.1 kg sled with a constant force of 23 N for one block (112 m). How much work did Georgie do? Answer in units J

Answer 1

First, find the work W done by Georgie.

W = Fd = (23 N)(112 m) = 2576 J

Next, find how much time it takes to deliver 2576 J with a power P of 150 watts.

W = Pt

t = W/P = (2576 J)/(150 watts) = 17.2 s