If the angular momentum of a body increases by 50%, its kinetic energy of rotation increases by

Options

A. `50%`
B. `25%`
C. `125%`
D. `100%`

Answer

C

Explanation

`KE_(1)=(1)/(2)(I^(2)omega^(2))/(I)=(1)/(2)(L_(1)^(2))/(I)` and `KE_(2)=(1)/(2)(L_(2)^(2))/(I)`
`(KE_(2))/(KE_(1))=((L_(2))/(L_(1)))^(2)=((1.5L_(1))/(L_(1)))^(2)=2.25`
`(KE_(2))/(KE_(1))-1=1.25 therefore (KE_(2)-KE_(1))/(KE_(1))=1.25`
`therefore (KE_(2)-KE_(1))/(KE_(1)) % = 125%`