Two identical discs are positioned on a vertical axis as shown in the figure. The bottom disc is rotating at angular velocity `omega_(0)` and has rotational kinetic energy `K_(0)`. Change in the rotational kinetic energy of the system is

Options

A. `K_(0)//2`
B. `-K_(0)//2`
C. `-K_(0)//4`
D. `K_(0)//4`

Answer

A

Explanation

`K=(L^(2))/(2I)` or `Kprop(1)/(I)` As `I` has doubled, so `K` will become half.