2
\includegraphics[max width=\textwidth, alt={}, center]{9bb53600-e7ba-4228-84ae-d8ddf7649387-2_350_688_493_731} Three coplanar forces act at a point. The magnitudes of the forces are \(5 \mathrm {~N} , 6 \mathrm {~N}\) and 7 N , and the directions in which the forces act are shown in the diagram. Find the magnitude and direction of the resultant of the three forces.
\(3 A\) and \(B\) are points on the same line of greatest slope of a rough plane inclined at \(30 ^ { \circ }\) to the horizontal. \(A\) is higher up the plane than \(B\) and the distance \(A B\) is 2.25 m . A particle \(P\), of mass \(m \mathrm {~kg}\), is released from rest at \(A\) and reaches \(B 1.5\) s later. Find the coefficient of friction between \(P\) and the plane. [6]