Two boys weighing 30 and 50 kg ran up the stairs to a height of 4 m in the same time 20

Two boys weighing 30 and 50 kg ran up the stairs to a height of 4 m in the same time 20 seconds. Which of them: A) did a great job B) developed a lot of power

Data: m1 (first boy) = 30 kg; m2 (second boy) = 50 kg; h (the height the boys climbed) = 4 m; t (rise time) = 20 s.

Constants: g (acceleration due to gravity) ≈ 10 m / s2.

1) Perfect work: A1 = F1 * S = m1 * g * h = 30 * 10 * 4 = 1200 J and A2 = 50 * 10 * 4 = 2000 J.

2) The power that the boys developed: N1 = A1 / t = 1200/20 = 60 W and N2 = 2000/20 = 100 W.

Answer: Because of the greater mass, the second boy did a great job and developed more power.