Mathematics 9709 · AS & A Level · Energy, work and power

Energy, work and power — practice question

A car with mass $1600\text{ kg}$ moves at a constant speed of $20\text{ m s}^{-1}$ up a straight road that makes an angle of $\sin^{-1} 0.12$ to the horizontal.
(a)[3]

Find the car’s change in potential energy over $30\text{ s}$.

(b)[3]

Given that the engine’s total work done in this time is $1960\text{ kJ}$, find the constant force that opposes the motion.

(c)[2]

Calculate, in kW, the power produced by the car engine.

(d)[3]

Find the car’s instantaneous deceleration if this power is reduced suddenly by $15\%$.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: Correct distance covered $s=30\times20$

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