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 the definition of the power, we have:

$$P=\dfrac{W}{t}=\dfrac{Fh}{t},$$ $$P=\dfrac{8.25\cdot 10^3\ N\cdot 2.10\ m}{1.05\ s}=1.65\cdot 10^4\ W.$$

Answer:

$P=1.65\cdot 10^4\ W.$