Mathematics 9709 · AS & A Level · Energy, work and power
Energy, work and power — practice question
A lorry with mass $7850\text{ kg}$ is moving on a straight slope that makes an angle of $3^\circ$ with the horizontal. A steady resistive force of $1480\text{ N}$ acts against the motion.
(i)[3]
Determine the power delivered by the lorry’s engine while it is climbing the hill at a steady speed of $10\text{ m s}^{-1}$.
(ii)[3]
Determine the engine power at the instant when the lorry is descending the hill at $15\text{ m s}^{-1}$ and has acceleration $0.8\text{ m s}^{-2}$.
Worked solution & mark scheme
This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Total resistive force: $F = 1480 + 7850\sin 3$” …