Mathematics 9709 · AS & A Level · Forces and equilibrium
Forces and equilibrium — practice question
At point O, three coplanar forces with magnitudes 10 N, 25 N and 20 N act in the directions shown in the diagram.
(a)[4]
With the component of the resultant force in the $x$-direction equal to zero, find $\alpha$, and hence find the magnitude of the resultant force.
(b)[5]
If instead $\alpha = 45$, find the magnitude and direction of the resultant of the three forces.
Worked solution & mark scheme
This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: “By resolving horizontally: $20\cos30=25\cos60+10\cos\alpha$” …