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.

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

multiply 2kg by latent heat of vap

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.