(i)[2]
Show that the train’s speed at $B$ is $35\,\text{m s}^{-1}$.
(ii)[3]
For the journey from $A$ to $B$, determine the work done by the train’s engine if the work done against the resistance to the train’s motion is $2.3 \times 10^6\,\text{J}$.
Mathematics 9709 · AS & A Level · Energy, work and power
Energy, work and power — practice question
A train with mass $200\,000\,\text{kg}$ travels along a level straight track. It goes past point $A$ at $28\,\text{m s}^{-1}$ and then later passes point $B$. At $B$, the power of the train’s engine is $1.2$ times the power of the train’s engine at $A$. Also, the driving force of the train’s engine at $B$ is $0.96$ times the driving force of the train’s engine at $A$.
Worked solution & mark scheme
This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Apply $P = Fv$ with the factors $1.2$ and $0.96$, for example $v_B = 1.2 \times 28 \div 0.96$” …
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