NEET2025PhysicsLaws of MotionActual
A uniform rod of mass 20 kg and length 5 m leans against a smooth vertical wall making an angle of 60^ 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 )
Options
- A100 N
- B100 3 ~N
- C200 N
- D200 3 ~N
Correct answer
B. 100 3 ~N
Step-by-step solution
N ₂= mg =200 ~N Taking torque about A : aligned & f _ s ~L 60^ + mg ~L 2 60^ = N ₂ ~L 60^ & f _ s ( 1 2 )+200 ( 1 2 ) 3 2 =200 3 2 & f _ s =100 3 ~N aligned