Answer:
Explanation:
In the whole process , angular momentum will be conserved because no external torque is acting on the system . The radius of circular path is reduced so angular velocity will be increased
I₁ x ω₁ = I₂ x ω₂
m r₁² x ω₁ = m r₁²ω₂
r₁² x ω₁ = r₂²ω₂
ω₂ = r₁² x ω₁ / r₂²
= ( 14 x 14 x 4) / ( 9 x 9 )
= 9.68 rad /s
Work done
= increase in rotational kinetic energy
= 1/2 x I₂ ω₂² - 1/2 x I₁ ω₁² ( I = m r² )
= 1/2 x .4 x .454 x( 9 x 2.54 x 10⁻² x 9.68 )² - 1/2 x .4 x .454 x( 14 x 2.54 x 10⁻² x 4 )²
= .4446 - 0.1837
= .261 J .
=
