Question

The rotational kinetic energy of two bodies of moment of inertia `9 kg m^(2)` and `1kg m^(2)` are same . The ratio of their angular momenta is
A. `1:3`
B. `1:9`
C. `9:1`
D. `3:1`

Answer 1

Correct Answer - D
`K.E._(1)=K.E._(2)`
`(1)/(2)L_(1)=(1)/(2)L_(2)`
`therefore ((L_(1))/(L_(2)))^(2)=(I_(1))/(I_(2))`
`(L_(1))/(L_(2))=sqrt((I_(1))/(I_(2)))=sqrt((9)/(1))=(3)/(1)`