Physics 9702 · AS & A Level · Equilibrium of forces

Equilibrium of forces — practice question

(a)[1]

State Newton’s first law in words.

(b(i))[2]

A log of mass $450\,\text{kg}$ is hauled up a slope by a wire joined to a motor, as shown in Fig. 3.1. The slope is inclined at $12^{\circ}$ to the horizontal. The frictional force on the log is $650\,\text{N}$. The log moves with constant velocity. Using the motion of the log, discuss whether it is in equilibrium.

(b(ii))[3]

Calculate the wire tension.

(b(iii))[2]

State and explain whether the log’s gain in potential energy per unit time is equal to the motor’s output power.

Worked solution & mark scheme

This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: Newton’s first law statement

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