The position vector of three particles of masses `m_1=2kg`.
`m_2=2kg` and `m_3=2kg` are `r_1=(2hati+4hatj+hatk)m`, `r_2=(hati+hatj+hatk)m` and `r_3=(2hatj-hatj-2hatk)m` respectivley. Find the position vector of their centre of mass.

Explanation

To find the position vector of the center of mass of the three particles, we can use the formula for the center of mass (COM):

\[ \vec{r}_{\text{COM}} = \frac{m_1 \vec{r}_1 + m_2 \vec{r}_2 + m_3 \vec{r}_3}{m_1 + m_2 + m_3} \]

### Step 1: Identify the masses and position vectors
Given:
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