Three bricks each of length L and mass M are arranged as shown from the wall. The distance of the centre of mass of the system from the wall is

Options

A. `L//4`
B. `L//2`
C. `(3//2)L`
D. `(5//6)L`

Answer

D

Explanation

`m_(1)=m_(2)=m_(3)=M`
`x_(1)=L//2,x_(2)=L,x_(3)=L+(L)/(4)=(5L)/(4)`
`x_(CM)=(m_(1)x_(1)+m_(2)x_(2)+m_(3)x_(3))/(m_(1)+m_(2)+m_(3))`
= `(Mxx((L)/(2)+L+(5L)/(4)))/(3M)=(11L)/(12)`