Two particles of masses 1kg and 2kg are located at `x=0` and `x=3m`. Find the position of their centre of mass.

Options

A. 2m from 1 kg
B. 2m from 2 kg
C. 1m from 1 kg
D. none of these

Answer

A

Explanation

Since, both the particles lie on x-axis, the COM will also lie on x-axis. Let the COM is located at `x=x`, then `r_1=` distance of COM from the particle of mass `1kg=x` and `r_2=` distance of COM from the particle of mass 2kg
`=(3-x)`
Using `r_1/r_2=m_2/m_1`
or `(x)/(3-x)=2/1 or x=2m`
Thus, the COM of the two particles is located at `x=2m`.