JEE Main202126 Feb 2021Morning ShiftPhysicsOscillationsActual
Assume that a tunnel is dug along a chord of the earth, at a perpendicular distance R 2 from the earth's centre, where R is the radius of the earth. The wall of the tunnel is frictionless. If a particle is released in this tunnel, it will execute a simple harmonic motion with a time period:
Options
- A1 2 π g R
- B2 π R g
- Cg 2 π R
- DImage is virtual, opposite side of convex mirror.
Correct answer
B. 2 π R g
Step-by-step solution
Force along the tunnel F = - G M m r R 3 cos θ F = - g m R x G M R 2 = g ,   r cos θ = x a = - g R x ω 2 = g R T = 2 π R g