(a)[1]
Define power in words.
(b(i))[3]
Fig. 3.1 shows a car moving at a speed of $22\text{ m s}^{-1}$ along a horizontal road. The car has a mass of $1500\text{ kg}$. A resistive force of $1200\text{ N}$ acts on the car. Calculate the force $F$ needed from the car to give an acceleration of $0.82\text{ m s}^{-2}$.
(b(ii))[2]
Calculate the power needed to cause this acceleration.
(c)[1]
The resistive force on the car is proportional to $v^2$, where $v$ is the car’s speed. Suggest why the car has a maximum speed.