Question

A disc and a ring having same mass M and radius R rotating about its axis which is normal to their plane.
If both have the same angular momentum, then the ratio of acceleration of the particles at the circumference of the disc to the ring is

• A. 1 : 2
• B. 2 :1
• C. 1:4
• D. 4:1

Answer 1

The correct option is D 4:1

Angular momentum, $L=I\omega \frac{M{R}^2}{2}{\omega }_1=M{R}^2{\omega }_2\Rightarrow {\omega }_1=2{\omega }_2\frac{a_1}{a_2}=\frac{{\omega }_1^{2}R}{{\omega }_2^{2}R}=4:1$