A climber of mass 70 kg ascends a rock face 200 m high in 1.5 hr. What power does she put out? (g = 9.80 m.s-2.)
A climber of mass 70 kg ascends a rock face 200 m high in 1.5 hr. What power does she put out? (g = 9.80 m.s-2.) |
|
The work done by the climber is her gain in potential energy:
mgh = 70 (kg) x 9.80 (m.s-2) x 200 (m) = 137000 J.
Since she gained this energy in 1.5 hr = 5400 s, her power output was 137000 (J) ÷ 5400 (s) = 25.4 W. (Not impressed? Try it!)
