Question

Three bricks 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

• A. L/4
• B. L/2
• C. (3/2)L
• D. (11/12)L
• E. (5/6)L

Answer 1

The correct option is D (11/12)L

using $X_{cm}=\frac{\sum m_i{x}_i}{m_i}$

$X_{cm}=\frac{M\frac{L}{2}+\frac{M}{L}+\frac{5M}{4L}}{3M}$

$X_{cm}=\frac{11L}{12}$