Physics (AS & A Level) · Oct / Nov 2019 · Paper 13 · Question 17

The maximum useful output power of a car travelling on a horizontal road is $P$. The total resistive force acting on the car is $kv^2$, where $v$ is the speed of the car and $k$ is a constant. Which equation is correct when the car is travelling at maximum speed?

1. A$v^3 = \dfrac{P}{k}$
2. B$v^2 = \dfrac{P}{k}$
3. C$v = \left(\dfrac{P}{k}\right)^2$
4. D$v = \left(\dfrac{P}{k}\right)^3$

As printed in the paper