Question

Two bodies have their moments of inertia I and 21 respectively about their axis of rotation. If their kinetic energies of rotation are equal, their angular momenta will be in the ratio

• A. 1:2
• B. $\sqrt { 2 } : 1$
• C. $1 : \sqrt { 2 }$
• D. 2 : 1

Answer 1

Answer: (C)

$1 : \sqrt { 2 }$

Answer 2

As, $\mathrm { K } _ { \mathrm { R } _ { 1 } } = \mathrm { K } _ { \mathrm { R } _ { 2 } }$

$\therefore \frac { 1 } { 2 } \mathrm { I } _ { 1 } \omega _ { 1 } ^ { 2 } = \frac { 1 } { 2 } \mathrm { I } _ { 2 } \omega _ { 2 } ^ { 2 }$

or …(i)

(Using (i))