(i)[4]
Determine the value of $R$, given that the car has acceleration $1.4\,\text{m s}^{-2}$ at a moment when its speed is $18\,\text{m s}^{-1}$ and the engine is operating at $22.5\,\text{kW}$.
(ii)[1]
State the rate of working of the car’s engine when the car is travelling with constant speed $15\,\text{m s}^{-1}$.