In this question use g=9.8g = 9.8g=9.8 m s−2^{-2}−2.
A uniform plank AB AB\,AB of length 6 m and mass 40 kg rests horizontally on two supports at C C\,C and DDD, where AC=1.5AC = 1.5AC=1.5 m and AD=4AD = 4AD=4 m.
A man of mass 80 kg stands on the plank at a distance y y\,y m from AAA.
Find the set of possible values of y y\,y for which the plank remains in equilibrium.
56 exam-style questions on OCR (MEI) A Level Maths 3.6 Rigid Bodies (A-level only), covering 3.6.1 Moment of a force (A-level only), 3.6.2 Equilibrium of a rigid body (A-level only), 3.6.3 Turning effect of forces (A-level only), and 3.6.4 Weight acting through a point (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.