Show that the coefficient of friction between \(P\) and the plane is \(\frac { 4 } { 3 }\).
A force of magnitude 10 N is applied to \(P\), acting up a line of greatest slope of the plane, and \(P\) accelerates at \(2.5 \mathrm {~m} \mathrm {~s} ^ { - 2 }\).