Consider a rigid body placed in a plane and acted on by several coplanar forces.
PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
Consider a rigid body placed in a plane and acted on by several coplanar forces.
(i) State the two independent conditions that must be satisfied for the body to remain in complete static equilibrium.
(ii) Give a reason why, if these conditions are satisfied, the algebraic sum of moments of all forces may be taken about any arbitrary point in the plane.
(iii) A uniform metre rule of weight 1.5 N is pivoted at its 50 cm mark and kept horizontal by suspending two weights W1 and W2 at the 20 cm and 80 cm marks respectively. Write, but do not solve, the two independent equations that express the conditions for equilibrium of the system.