A crate of weight 15 N lies on a rough slope inclined at an angle of 20∘ 20^\circ\,20∘ to the horizontal. A horizontal force of 12 N acts on the crate and the crate is in equilibrium on the point of slipping up the slope.
Find the coefficient of friction between the crate and the slope.
The 12 N force is removed. Determine whether or not the crate moves.