A ring performs pure rolling on a horizontal surface and its state at some instant of time is shown in figure.

Options

A. K.E. stored in the portion AB is same as K.E. stored in the portion CD
B. K.E. stored in the portion AB is same as KE. stored in the portion BC
C. K.E. stored in the portion ABC is same as K.E. stored in the portion CDA
D. K.E. stored in the portion ABC is less than K.E. stored in the portion CDA

Answer

B, D

Explanation

Here each point on the ring is moving due to translatory motion (v) as well as due to rotational motion (ro). Angle between these two velocity vectorsis less than 90° for the portion CDA whereas it is greater than 90° for the portion ABC. Hence net velocity of the particles in the portion CDA is more than the particles in the portion ABC. Further distribution of magnitude of velocity is same for the portions AB and BC. Similarly distribution of magnitude of velocity is same for the portions CD and DA.
In the above discussion we can understand that options (b) and (d) are correct.