Question

The radius of gyration of a thin spherical shell of radius R about its tangent is

• A. $\sqrt { \frac { 2 } { 3 } } R$
• B. $\sqrt { \frac { 3 } { 5 } } R$
• C. $\sqrt { \frac { 2 } { 5 } } R$
• D. $\sqrt { \frac { 5 } { 3 } } R$

Answer 1

Answer: (D)

$\sqrt { \frac { 5 } { 3 } } R$

Answer 2

I_tangent = I_cm + MR² = $\frac { 2 } { 3 } M R ^ { 2 } + M R ^ { 2 } = \frac { 5 } { 3 } M R ^ { 2 }$ ⇒ Mk²

=

⇒ k = $\sqrt { \frac { 5 } { 3 } } R$

(4) is the correct choice