NTA Abhyas JEE Main2020PhysicsOscillationsPractice
A highly rigid cubical block A of small mass M and side L is fixed rigidly on to another cubical block B of the same dimensions and of low modulus of rigidity η such that the lower face of A completely covers the upper face of B . The lower face of B is rigidly held on a horizontal surface. A small force F is applied perpendicular to one of the side faces of A . After the force is withdrawn, block A executes small os
Options
- A2 π M η L
- B2 π M η L
- C2 π M L η
- D2 π M η L
Correct answer
D. 2 π M η L
Step-by-step solution
Modulus of rigidity, η = F A . θ Here, A = L 2 And θ = x L Therefore, restoring force is F = − η A θ = − η L x Or acceleration, a = F M = − η L M x Since, a ∝ x , oscillations are simaple harmonic in nature, time period of which is given by T = 2 π | d i s p l a c e m e n t a c c e l e r a t i o n | = 2 π | x a | = 2 π M η L