# A rifle is aimed horizontally at a target 50 m away. The bullet hits the target 2.0 cm below the aim point. What was the bullet's flight time, and the speed it left the barrel?

Nov 17, 2015

$\left(a\right) .$

$0.064 \text{s}$

$\left(b\right) .$

$781.2 \text{m/s}$

#### Explanation:

$\left(a\right) .$

To get the time of flight we consider the vertical component of motion:

$s = \frac{1}{2} \text{g} {t}^{2}$

$\therefore t = \sqrt{\frac{2 s}{g}}$

$t = \sqrt{\frac{2 \times 0.02}{9.8}}$

$t = 0.064 \text{s}$

$\left(b\right) .$

The horizontal component of velocity is constant so:

$v = \frac{s}{t} = \frac{50}{0.064} = 781.2 \text{m/s}$