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. `((11)/(12)) L`

Answer

D

Explanation

From figure ,
`x_(1) = (L)/(2), x_(2) = (L)/(2) + (L)/(2) = L , x_(3) = (L)/(2) + (L)/(4) + (L)/(2) = (5L)/(4)`
`therefore X_(CM) = (m_(1) x_(1) + m_(2) x_(2) + m_(3) x_(3))/(m_(1) + m_(2) + m_(3))`
`= (M xx (L)/(2) xx M xx L + M xx (5L)/(4))/(M + M + M) = ((11)/(4) ML)/(3M) = (11)/(12) L`