A bullet is to be fired with a speed of `2000 m//s` to hit a target `200 m` away on a level ground. If `g = 10 m//s^(2)`, the gun should be aimed

Options

A. directly at the target
B. 5 cm below the target
C. 5 cm below the target
D. 2 cm above the target

Answer

C

Explanation

Let t be time taken by the bullet to hit the target.
`:. 200 m = 2000 ms^(-1)t rArr t = (200m)/(2000 m^(-1)) = (1)/(10)s`
For vertical motion, here, `u = 0`
`:.h = (1)/(2) g t^(2)`
`h = (1)/(2) xx 10 xx ((1)/(10))^(2) = (1)/(20) m = 5m`
`:.` Gun should be aimed 5 cm above the target.