Mathematics 9709 · AS & A Level · Energy, work and power
Energy, work and power — practice question
A car with mass $800\,\text{kg}$ is travelling uphill on a slope making an angle of $\theta^\circ$ with the horizontal, where $\sin\theta = 0.15$. Its initial speed is $8\,\text{m s}^{-1}$. Twelve seconds later, it has gone $120\,\text{m}$ up the slope and its speed is $14\,\text{m s}^{-1}$.
(i)[3]
Find the change in the car’s kinetic energy and the change in its gravitational potential energy.
(ii)[3]
The car engine is operating at a steady power of $32\,\text{kW}$. Find the total work done against the resistive forces over the twelve seconds.
Worked solution & mark scheme
This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: “An attempt is made to use KE and/or PE with the correct dimensions” …