A uniform metal rod AB AB\,AB of mass 12 kg and length 4 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 rod and the ground is 0.5. The rod makes an angle θ \theta\,θ with the ground.
Given that the rod is on the point of slipping.
Find the magnitude of the frictional force of the ground on the rod.
Find the value of θ\thetaθ, to 1 decimal place.
53 exam-style questions on OCR A Level Maths 3.4 Moments (A-level only), covering 3.4.1 Moment of a force (A-level only), 3.4.2 Equilibrium of a rigid body (A-level only), and 3.4.3 Moments in static contexts (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.