Find the location of centre of mass of a uniform semicircular plate of radius `R` and mass `M`.

Explanation

The centre of mass of semicircular disc `= r_(cm)= int ydm// int dm` where `y_(cm)=2y//pi=C.M.` of the semicircular ring of radius y.
& `dm = {(M)/(pi r^(2)//2)}{pi ydy}=(2M)/(r^(2))ydy`
`r_(cm)=(int_(0)^(r )((2y)/(pi))((2M)/(r^(2))ydy))/(M)=(4r)/(3pi)` along y - axis