A bullet is to be fired with a speed of 2000 ms-1 to hit a target 200 m away on a level ground. If g=10 text ms-2, the gun should be aimed

Question

A bullet is to be fired with a speed of 2000 ms-1 to hit a target 200 m away on a level ground. If g=10 text ms-2, the gun should be aimed (A) directly at the target (B) 5 cm below the target (C) 5 cm above the target (D) 2 cm above the target

Tardigrade Admin · Accepted Answer

Horizontal distance of target is 200 m.
Speed of bullet

= 2000 m s^{- 1}

.
Time taken by bullet to cover the horizontal distance

t = \frac{200}{2000} = \frac{1}{10} s

During

\frac{1}{10}

s,
the bullet will fall down vertically due to gravitational acceleration. Therefore, height above the target, so that the bullet hits the target is

h = u t + \frac{1}{2} g t^{2} = (0 \times \frac{1}{10}) + \frac{1}{2} \times 10 \times (0.1)^{2}

= 0.05 m = 5 c m

Q. A bullet is to be fired with a speed of 2000 $m s^{- 1}$ to hit a target $200 m$ away on a level ground. If $g = 10 m s^{- 2},$ the gun should be aimed

directly at the target

5 cm below the target

5 cm above the target

2 cm above the target

2 cm below the target