Question

A bullet is fired with a speed of $1500m/s$ in order to hit a target $100m$ away. If $g=10m/s^2$ the gun should be aimed.

• A. $5cm$ above the target
• B. $10cm$ above the target
• C. $2.2cm$ above the target
• D. directly towards the target

Answer 1

Answer: (C)

$2.2cm$ above the target

Time taken by bullet to hit the target $t=\frac{100}{1500}=\frac{1}{15}s$

So, vertical distance traveled by bullet in this time,

$S_y=\frac{1}{2}g{t}^2$

Or $S_y=\frac{1}{2}\times 10\times (\frac{1}{15}{)}^2=0.022m=2.2cm$

So, the gun must be aimed at 2.2 cm above the target.

Option C is correct.