Question

A bullet with muzzle velocity `100 m s^-1` is to be shot at a target `30 m` away in the same horizontal line. How high above the target must the rifle be aimed so that the bullet will hit the target ?
.
A. `45m`
B. `45cm`
C. `45mm`
D. `30cm`

Answer 1

Correct Answer - B
A bullet …………….
Horizontal range of bullet is `30 m (V^(2)sin 2theta)/(9)= 30 implies`
`sin2theta = 0.03`
for small `theta` , `sin theta ~= theta`
`implies 2theta ~= 0.03 implies` , `theta = 0.015`
height to be aimed `= 30 tan theta ~= 30(theta)`
`~=30(0.15)`
`=45 cm`