Answer:
Step-by-step explanation:
Let the initial rotational inertia be I and final rotational inertia be I / 6 .
Let the initial angular velocity be ω₁ and final angular velocity be ω₂.
Applying conservation of angular momentum law
I x ω₁ = I / 6 x ω₂
6 ω₁ = ω₂
initial rotational kinetic energy = 1/2 I x ω₁ ²
Final rotational kinetic energy = 1/2 ( I / 6 ) x ω₂ ²
Final rotational kinetic energy / initial rotational kinetic energy
= ( 1 / 6 ) x ω₂ ² / ω₁ ²
= ω₂ ² / 6ω₁ ²
= 36 ω₁ ² / 6ω₁ ²
= 6 .