Related to
IB Physics Topic A4 Rigid body mechanics;
A-level Applied Maths. Mechanics, Year 2, Exexcel, OCR, AQA. Moments.
Question from I.Y.G.B.
The figure above shows a ladder AB resting in equilibrium with one end A on rough horizontal ground and the other end B against a smooth vertical wall. The ladder is modelled as a uniform rod of length 5 metres and mass 20 kg, and lies in a vertical plane perpendicular to the wall and the ground, inclined at an angle ϕ to the horizontal.
When a person, which is modelled as a particle, of mass 60 kg stands at a point C on the ladder, where AC = 4 metres the ladder is at the point of slipping. Given that the coefficient of friction between the ladder and the ground is 1/4, find …
a) … the magnitude of the frictional force of the ground on the ladder.
b) … the value of ϕ , to the nearest degree.