A girl weighs 200 newtons. How

much work does she do

climbing 10 meters of steps?

W=fscosx

w=fscos0 {as x (angle between force and displacement) = 0 because force and displacement is in same direction}

w=200*10

w=2000 joules

When she gets to the top, she has (200x10) = 2000 more joules of potential energy than she had at the bottom. But unfortunately, she has to do a lot more work than that in order to get there. She has to lift a leg, put it down, and then extend it, for each step, for example. The human body is not 100% efficient.