Question

A uniform rod of mass 20 kg and length 5 m leans against a smooth vertical wall making an angle of \(60^\circ\) with it. The other end rests on a rough horizontal floor. The friction force that the floor exerts on the rod is (take \(g = 10\) m/s\(^2\)):

• A. \( 100 \sqrt{3} \text{ N} \)
• B. \( 200 \text{ N} \)
• C. \( 200 \sqrt{3} \text{ N} \)
• D. \( 100 \text{ N} \)

Hint:

For equilibrium problems involving rods or beams, remember to apply the conditions of zero net force (both horizontal and vertical components) and zero net torque about any convenient point. Choosing the pivot point at one of the contact points often simplifies the torque equation by eliminating the torque due to the forces acting at that point.