A gun weighing 100 kg is used to fire an iron ball weigh ing 1 kg horizontally from a cliff of height 500 m above the ground. The ball falls 400 m away from the bottom of the cliff. What is the recoil velocity of the gun? `(Take g =10 ms^(-2))`

Options

A. `0.8 ms^(-1)`
B. `0.4 ms^( -1)`
C. `1.2 ms^(-1)`
D. `0.2 ms^(-1)`

Answer

b

Explanation

Here `h=(1)/(2)g t^ (2)`

`:.t^(2)=(2h)/(g)=(2xx500)/(10)`
`t=10 sec`
Also `x=ut`
`:.u=(x)/(t)=(400)/(10)`
`=40 m sec^(-1)`
Now recoil velocity `V=(mu)/(M)`
`V=(1xx40)/(100)=0.4 ms^(-1)`
Hence (b) is the right choice