A plank AB 3m long weighing 20kg with its centre of gravity 2m from the end A carries a load of mass 10kg at the end A. it rests on two supports at C and D
1. compute the values of the reaction forces R1 and R2 at C and D.
2. How far from D, and on what side of it, must a mass 24kg be placed on the plank so as to make the reactions equal ? What are their values ?
3. without this 24kg, what vertical force applied at B will just lift the plank clear of D? What is then the reaction at C?