Correct option is C
Given:
1. Earth is an axially symmetric, freely rotating rigid body.
2. The ratio of the principal moments of inertia about the axis of symmetry Iz and an axis perpendicular to it Ix=Iy is given as Iz:Ix=33:32 .
3. T0 is the time taken by Earth to make one rotation around its axis of symmetry.
The time period of precession T of a symmetric rigid body is given by:
T=(Iz−Ix)ω2πIx
where:
Ix is the moment of inertia about an axis perpendicular to the axis of symmetry.
Iz is the moment of inertia about the axis of symmetry.
ω is the angular velocity of Earth's rotation around its axis of symmetry.
Solution:
Expressing Moments of Inertia Using the Given Ratio:
- We are given Iz:Ix=33:32
Let Ix=32k and Iz=33k for some constant k.
2. Calculate Iz−Ix:
Iz−Ix=33k−32k=k
3. Angular Velocity ω: - The angular velocity ω of Earth’s rotation is related to the rotation period T0 by: ω=T02π
4. Substitute into the Precession Period Formula: Substitute Ix=32k,Iz−Ix=k, and ω=T02π into the formula: T=k⋅T02π2π⋅32k
T=k⋅2π2π⋅32k⋅T0=32T0
Final Answer: The time period of precession is closest to: 32T0