A uniform scaffolding plank AB AB\,AB of mass 15 kg and length 6 m is at rest with one end A A\,A on rough horizontal ground and the other end B B\,B against a smooth vertical wall. The coefficient of friction between the plank and the ground is 0.35. The plank makes an angle θ \theta\,θ with the ground.
Given that the plank is on the point of slipping.
Find the magnitude of the frictional force of the ground on the plank.
Find the value of θ\thetaθ, to 1 decimal place.