Two paper screens `A and B` are separated by `150 m`. A bullet pierces `A and B`. The hole in `B` is `15 cm` below the hole in `A`. If the bullet is travelling horizontally at the time of hitting `A`, then the velocity of the bullet at `A` is `(g = 10 ms^-2)`

Explanation

Equation of motion in x- direction, `100 = v xx t`
`rArr t = (100)/(v)`…(i)
In y - direction,
`0.1 = 1//2 xx 10 xx t^2` …(ii)
`0.1 = 1//2 xx 10 xx (100//v)^2`
From Eqs (i) and (ii), we get
`u = 700 m s^-1`.