Question

A bom of mass `1 kg` is thrown vertically upwards with a speed of `100m//s`. After 5 seconds, it explodes into two fragments. One fragment of mass `400 gm` is found to go down with a speed of `25m//s`. What will happen to the second fragment just after the explosion ? `(g=10ms^(-1))`
A. It will go upwards with speed `40 m//s`
B. It will go upwards with speed `100m//s`
C. It will go upwards with speed `60m//s`
D. It will go downwards with speed `40 m//s`

Answer 1

Correct Answer - B
Velocity of bomb just before explosion.
`upsilon=u-g t=100-10xx5=50m//s`
Applying principle of conservation of linear momentum, `m upsilon=m_(1)upsilon_(1) +m _(2)upsilon_(2)`
`1xx50=(400)/(1000)(-25)+(600)/(1000)upsilon_(2)`
`upsilon_(2)=100 m//s,` upwards.