A shell of mass `200g` is ejected from a gun of mass `4 kg` by an explosion that generate `1.05 kJ` of energy. The initial velocity of the shell is

Options

A. `40 ms^(-1)`
B. `120 ms^(-1)`
C. `100ms^(-1)`
D. `80ms^(-1)`

Answer

C

Explanation

`underset("gun")(m_(1)upsilon_(1))=underset("shell")(m_(2)upsilon_(2))`
`4xxupsilon_(1)=(200)/(1000)xxupsilon_(2)`
`(upsilon_(2))/(upsilon_(1))=20" …(1)"`
`(1)/(2)m_(1)upsilon_(1)^(2)+(1)/(2)m_(2)upsilon_(2)^(2)=1.05xx10^(3)`
`2upsilon_(1)^(2)+(1)/(10)upsilon_(2)^(2)=1.05xx10^(3)" ...(2)"`
By equation (1) and (2)
`upsilon_(2)=100m//s`