Question

A 10-g rifle bullets requires a speed of a 400 m/s in traversing a barrel 50 cm long. find the average acceleration and acceleration force?

Answer 1

Given:

$m=0.01\:\rm kg$

$v_0=400\:\rm m/s$

$v_f=0\:\rm m/s$

$d=0.5\:\rm m$

The energy-work theorem says

$$\Delta E_k=W$$

$$\frac{mv_0^2}{2}=Fd$$

The average force

$$F=\frac{mv_0^2}{2d}=\frac{0.01*400^2}{2*0.5}=1600\:\rm N$$

Acceleration

$$a=\frac{F}{m}=\frac{1600}{0.01}=1.6*10^5\:\rm m/s^2$$