1 A particle of mass 2 kg is initially at rest on a rough horizontal plane. A force of magnitude 10 N is applied to the particle at \(15 ^ { \circ }\) above the horizontal. It is given that 10 s after the force is applied, the particle has a speed of \(3.5 \mathrm {~m} \mathrm {~s} ^ { - 1 }\).

1. Show that the magnitude of the frictional force is 8.96 N , correct to 3 significant figures.
2. Find the coefficient of friction between the particle and the plane.