Determine the centre of gravity of a thin homogeneous plate having the form of a rectangle with sildes r and `2r` from which a semicircle with a radius r is cut out of figure.

Answer

`Oc = (2pi)/(3(4 - pi))`

Explanation

`x_(cm) = ((rho2r^(2)) (r )/(2) - (rho(pir^(2))/(2)) ((4r)/(3pi)))/((rho2r^(2)) - (rho(pir^(2))/(2)))= (2r)/(3(4 - pi))`