Thread: physics

a 60 kg woman runs up a staircase 15 m high (vertically) in 20 s. (a) how much power does she expend? (b) what is her horsepower rating?

Originally Posted by twistedmexican

a 60 kg woman runs up a staircase 15 m high (vertically) in 20 s. (a) how much power does she expend? (b) what is her horsepower rating?

Work done is equal to the change in potential energy which is:

m*g*h=60*9.81*15=8829 Joules

This is done in 20 seconds so the avaerage power is 8829/20 = 441.45 Watts.

In horespower this is 441.45*0.00134=0.592 hp.

RonL