Question

What is the power output of a cyclist moving at a steady speed of 5ms-1 along a level road against resistance of 20N

Answer 1

$\text{according to Newton's 3 law, the action force is equal in magnitude and opposite}$ $\text{in direction to the reaction force}$

$F=20;\ P= F*V*\cos(\alpha)\ ;\alpha= 0$

$P= 20*5*1 =100 \text{ watt}$

Answer: $P= 100 \text{ watt}$