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\includegraphics[max width=\textwidth, alt={}, center]{f14ab5b6-f9eb-46a5-b5a6-3d34433313c6-08_615_693_260_726}
Three coplanar forces of magnitudes \(10 \mathrm {~N} , 25 \mathrm {~N}\) and 20 N act at a point \(O\) in the directions shown in the diagram.
- Given that the component of the resultant force in the \(x\)-direction is zero, find \(\alpha\), and hence find the magnitude of the resultant force.
- Given instead that \(\alpha = 45\), find the magnitude and direction of the resultant of the three forces.