JEE Main2003PhysicsRotational MotionActual
A circular disc X of radius R is made from an iron plate of thickness t , and another disc Y of radius 4 R is made from an iron plate of thickness t 4 . Then the relation between the moment of inertia I _ X and I _ Y is
Options
- AI _ Y =32 I _ x
- BI _ Y =16 I _ x
- CI _ Y = I _ X
- DI _ Y =64 I _ X
Correct answer
D. I _ Y =64 I _ X
Step-by-step solution
I = 1 2 mR or M t R ^2 For disc X, I_x= 1 2 (m)(R)^2= 1 2 ( r^2 t ) .(R)^2 For disc Y, I_y= 1 2 [ (4 R)^2 t / 4 ][4 R]^2 I_x I_y = 1 (4)^3 I_y=64 I_x