Mathematics 9709 · AS & A Level · Forces and equilibrium

Forces and equilibrium — practice question

Three coplanar forces with magnitudes $17\,\text{N}$, $51\,\text{N}$ and $34\,\text{N}$ act at point $O$ in the directions indicated in the diagram, with $\tan \alpha = \frac{15}{8}$.
(a)[6]

Determine the magnitude and the direction of the resultant of the three forces.

(b)[2]

The $51\,\text{N}$ force is changed to a force of size $P\,\text{N}$ acting in the same direction. The resultant of the three forces then lies along the positive $x$-direction. Determine $P$.

Worked solution & mark scheme

This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: All forces are correctly broken down into components.

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