Question

The moment of inertia of a body is I and its coefficient of linear expansion is a if temperature of body rises by a small amount DT. Then change in moment of inertia about the same axis –

• A. a I DT
• B. 2 a I DT
• C. 4 a I DT
• D. $\frac { \alpha \mathrm { I } \Delta \mathrm { T } } { 2 }$

Answer 1

Answer: (B)

2 a I DT

Answer 2

Let I = mr²

= $\frac { 2 \Delta \mathrm { r } } { \mathrm { r } }$ = 2 a DT

or $\Delta \mathrm { I } = 2 \alpha \mathrm { I } \Delta \mathrm { T }$