An open , water tight railway wagon of mass `5 xx 10^(3)` kg is moving at an initial velocity `1.2 ` m/s without friction on a railway track . Rain drops fall vertically downwards into the wagon . The velocity of the wagon after it has collected `10^(3)` kg of water will be

Options

A. `0.5 m//s`
B. `2 m//s`
C. `1 m//s`
D. `1.5 m//s`

Answer

C

Explanation

`COLM rArr m_(1)u_(1) + m_(2)u_(2) = (m_(1) + m_(2))v`
`5 xx 10^(3) xx 1.2 + 0 = (5 + 1) xx 10^(3) xv rArr v = 1 m//s`