A particle of mass 0.5 kg is held at rest at a point \(P\), which is at the bottom of an inclined plane. The particle is given an impulse of 1.8 N s directed up a line of greatest slope of the plane.
- Find the speed at which the particle starts to move. [2]
The particle subsequently moves up the plane to a point \(Q\), which is 0.3 m above the level of \(P\).
- Given that the plane is smooth, find the speed of the particle at \(Q\). [4]
It is given instead that the plane is rough. The particle is now projected up the plane from \(P\) with initial speed 3 ms\(^{-1}\), and comes to rest at a point \(R\) which is 0.2 m above the level of \(P\).
- Given that the plane is inclined at 30° to the horizontal, find the magnitude of the frictional force on the particle. [4]