Three identical particle each of mass `1 kg` are placed with their centres on a straight line. Their centres are marked `A, B and C` respectively. The distance of centre of mass of the system from `A` is.

Options

A. `(AB + AC + BC)/(3)`
B. `(AB + AC)/(3)`
C. `(AB + AC)/(3)`
D. `(AB + BC)/(3)`

Answer

B

Explanation

(b) `m_1 = m_2 = m_3 = 1 kg`
`x_(cm) = (m_1 x_1 + m_2 x_2 + m_3 x_3)/(m_1 + m_2 + m_3)`
where `x_1 = 0, x_2 = AB, x_3 = AC`.
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