1.

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 ?

Answer»

Goes UPWARDS with `40 ms^(-1)`
Goes upwards with `100 ms^(-1)`
Goes upwards with `60 ms^(-1)`
Goes downwards with `40 ms^(-1)`

Solution :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.


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