Physics 5054 · O Level · Energy, work and power

Energy, work and power — practice question

Fig. 9.1 displays a large container ship moving in a straight line at constant speed. The resistive force on the ship is $2.8 \times 10^{6}\,\text{N}$.
(a(i))[2]

Calculate the work done against the resistive force on the ship during $1.0\,\text{s}$.

(a(ii))[2]

State the energy transfer that is occurring while the ship travels at constant speed.

(b(i))[2]

Calculate the ship’s initial deceleration.

(b(ii))[2]

Suggest and explain how the ship’s deceleration alters as its speed falls.

(b(iii))[2]

On Fig. 9.2, sketch a possible speed-time graph for the ship as it slows to rest.

(b(iv))[2]

Explain how the ship’s distance travelled can be obtained from the speed-time graph.

(c(i))[1]

State the relationship used to define efficiency.

(c(ii))[2]

Calculate the rate at which energy is wasted by the engines.

Worked solution & mark scheme

This 15-mark question has a full step-by-step worked solution and mark scheme. One marking point: WD = F \times x

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