Answer to Question #96345 in Mechanics | Relativity for Alaa

Question

A rifle is found to give the bullet a muzzle velocity of 485 m/s the barrel is 80cm long
a) how much time is the bullet moving in the barrel?
b) what is the average acceleration of the bullet?

Answer 1

The movement of the ball is evenly accelerated.

We can write

$2as=v^2-{v_0}^2 (1)$

In our case, v₀=0m/s, v=485 m/s, s=0.8 m

Using (1) we get

$a=\frac{ v^2}{2s} (2)$

We have

a=147015 m/s²

The acceleration is given by formula

$a=\frac{v-v_0}{t} (3)$

Using (3) we get

$t=\frac{v-v_0}{a} (4)$

Answer

a)     0.0033 s

b)     147015 m/s²