The centre of mass of the shaded portion of the disc is :
(The mass is uniformly distributed in the shaded portion)

Options

A. `R/20` to the left of A
B. `R/12` to the left of A
C. `R/20` to the right of A
D. `R/12` to the right of A

Answer

A

Explanation

`A_(1)=piR^(2),A_(2)=(piR^(2))/16`
`x_(1)=0, x_(2)=(3R)/4`
`x_(cen)=(0-(piR^(2))/16xx(3R)/4)/(piR^(2)-(piR^(2))/16)=-R/20`