A uniform ladder AB AB\,AB has length 5 m and mass 18 kg. It rests with A A\,A on rough horizontal ground and B B\,B against a smooth vertical wall, making an angle of 60∘ 60^\circ\,60∘ with the ground. A painter of mass 70 kg stands 3.5 m from AAA, measured along the ladder. The painter is modelled as a particle.
Use g=9.8g=9.8g=9.8 m s−2^{-2}−2 throughout.
By taking moments about AAA, find the magnitude of the contact force exerted by the wall at BBB.
Find the magnitude of the resultant contact force exerted by the ground on the ladder at AAA.
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.