An isolated particle of mass `m` is moving in horizontal plane` xy` along the `x`-axis, at a certain height above the ground. It suddenly explodes into two fragment of masses `m//4` and `3m//4`. An instant later, the smaller fragment is at `y=+15` cm. The larger fragment at this instant is at

Options

A. y =-5m
B. y=+20cm
C. y=+5cm
D. y=-20cm

Answer

A

Explanation

Center of mass will not move along y-axix.
or `Y_(CM) = 0(always)`
`Y_(CM) = ((m_(1)y_(1) + m_(2)y_(2))/(m_(1)+m_(2))` `{therefore m_91) = m/4, m_(2) = (3m)/4}`
`0=(m//4)15+(3m//4)(y_(2))/(m//4+3m//4)`
`rArr (-15/4) = (3m)/(4) (y^(2)) rArr y_(2) = -5cm`