Four particles `A, B, C and D` of masses `m, 2m, 3m and 4m` respectively are placed at corners of a square of side `x` as shown in Fig.

Locate the centre of mass.

Explanation

Taking `A` as origin, co-ordinates of `A (0,0), B (x, 0), C(x , x), D(0, x)`
`x_(cm) = (m xx 0 + 2m xx x+ 3m xx x+ 4m xx 0)/(m + 2m + 3m + 4m) = (x)/(2)`
`y_(cm) = (m xx 0 + 2m xx 0 + 3m xx (x) + 4m xx (x))/(m + 2m + 3m + 4m)`
`= (7)/(10)x`