A man of mass 85 kg runs up a flight of stairs of height 4.6 m in a time period
of 12 s.
a) Calculate the man’s power rating when doing this.
b) A girl achieves a power rating of 70% of the man’s power rating wh en she scales the stairs in a time of 9.6 s. Calculate the mass of the girl.

Respuesta :

Explanation:

a) Power = work / time = force × distance / time

P = Fd/t

P = (85 kg × 9.8 m/s²) (4.6 m) / (12 s)

P ≈ 319 W

b) P = Fd/t

0.70 (319 W) = (m × 9.8 m/s²) (4.6 m) / (9.6 s)

m = 47.6 kg