Q.
A hanging object cannot be considered as a point mass and it oscillates about a fixed axis which does not pass through its centre of mass uniform rod of mass M and length L. The rod is pivoted at one end and hangs vertically in equilibrium with its centre of mass vertically below the point of suspension. The rod is slightly at the lower end and released. It then oscillates in a vertical plane in a simple harmonic manner, at any instant angular displacement of the rod from its vertical position is θ assuming small θ, equation of motion of the rod can be expressed as(Here I is the moment of inertia of the rod about the axis about which the rod oscillates )
see full answer
Talk to JEE/NEET 2025 Toppers - Learn What Actually Works!
Real Strategies. Real People. Real Success Stories - Just 1 call away
An Intiative by Sri Chaitanya
a
Idθdt=Mglθ
b
Id2θdt2=−Mgl2θ
c
Id2θdt2=−Mglθ
d
Id2θdt2=−Mglθ
answer is B.
(Unlock A.I Detailed Solution for FREE)
Ready to Test Your Skills?
Check your Performance Today with our Free Mock Test used by Toppers!
Take Free Test
Detailed Solution
For an object executing angular simple harmonic motion. τ=cθ Where, τ=Iα, Therefore, Iα=−cθWhere d2θdt2=α and Restoring torque acting on a rod after a small displacement θ, about an axis passing through point of contact O with the curved path,τ=−Mgrsinθ , for small angles sinθ≈θ Therefore, τ=−cθ=−Mgl2θ……………….(1)Therefore Id2θdt2=−Mgl2θ is the equation of angular simple harmonic motion.
Watch 3-min video & get full concept clarity