Two persons A and B of weight `80 kg` and `50 kg` respectively are standing at opposite ends of a boat of mass `70 kg` and length `2 m` at rest. When they interchange their positions then displacement of the centre of mass of the boat will be :-

Options

A. `60 cm` towards left
B. `30 cm` towards right
C. `30 cm` towards left
D. stationary

Explanation

`Deltabar(x) = (m_(1)Deltax_(1) + m_(2)Deltax_(2) + m_(3)Deltax_(3))/(m_(1) + m_(2) + m_(3))`
`Deltabar(x) = ((80 xx 2) - (50 xx 2) + (70 xx 0))/(80 + 50 + 70)`
`= 3 cm` towards right