A bomb of mass 1 kg is thrown vertically upwards with a speed of `100 ms^(-1)` After 5 sec. it explodes into two fragments. One of mass 400 g is found to go down with a speed of `25 ms6(-1)` what happens to the second justafter the explosion ?

Options

A. Goes upwards with `40 ms^(-1)`
B. Goes upwards with `100 ms^(-1)`
C. Goes upwards with `60 ms^(-1)`
D. Goes downwards with `40 ms^(-1)`

Answer

b

Explanation

Speed of bomb after `5 S =upsilon`
`upsilon = 100` - `10 xx 5 = 50 ms^( -1)`
Applying conservation of momentum
`1xx50=-(400)/(1000)xx25+(600)/(1000)xxV`
`60=(600)/(1000)V` or `V=100ms^(-1)`(upwards)
(b) is the choice.