Two bocks of masses 10 kg and 20 kg are placed on the X-axis. The first mass is moved on the axis by a distance of 2 cm. By what distance should the second mass be moved to keep the position of the centre of mass unchanged?

Explanation

Two masses `m_1 and m_2` are placed on the X-axis.
`m_1=10kg, m_2=20kg`
`the first mass is displaced by distance of 2 cm.
`:. X_(cm)=(m_1x_1+m_2x_2)/(m_1+m_2)`
`=(10xx2+20x_2)/30`
`rarr 0=(20+20x_2)/30`
`rarr 20+20x_2=0`
`rarr 20=-20x_2`
`rarr x_2=-1` `:. ` Second mass should be displaced by a distance 1 cm towards left so as to keep the position of centre of mass unchanged.