Physics Question on Motion in a plane

Question

A bullet is fired from the gun with a speed of 1000 $ms^{ -1}$ in order to hit a target s = 100 m away. At what height above the target should by gun be aimed? (The resistance of air is neglegible and g = 10 $ms^{ - 2}$

Answer 1

Solution

The time taken to cover the horizontal distance of 100 m from the gun to the target is given by t = $\frac{ 100 }{ 1000 } = 0.1 s$ During this time, the bullet will fall down vertically under gravity. Hence, height h = ut + $\frac{ 1}{2} gt^2$ = 0 + $\frac{ 1}{2} \times 10 \times (0.1)^2$ = 5 $\times 0.01 = 0.05 \, m =$ 5 cm