A man pushes a lawn mower on a level lawn with a force of 193 N. If 39% of this force is directed downward, how much power does he expend in pushing the mower 4.9 m in 12 s?

Answer 1

Fn = 193 - 0.39*193 = 117.73 = Net force.

Power = Fn * d/t
Power = 117.73 * 4.9/12 = 48.1 J/s =
48.1 Watts.