Answer to Question #143684 in Physics for Sydney

Question

An elephant lifts a fallen tree by exerting a force of 8.25 x 103 N upward. If she lifts the tree 2.10 m in 1.05 seconds, how much power does she use?

Answer 1

By definition, the power is:

$$P = \dfrac{F\cdot s}{t}$$

where $F = 8250N$ is the exerted force, $s = 2.1m$ is the distance and $t = 1.05s$ is a time. Thus, obtain:

$$P = \dfrac{8250\cdot 2.1}{1.05} =16500\space W = 16.5\space kW$$

Answer. 16500 W or 16.5 kW.