Question

A 5 kg rifle fires a bullet with speed of 500 ms-1. Find
the ratio of the distance the rifle move backward while the
bullet is in the barrel to the distance the bullet moves
forward?
(1) 1/600
(2) 1/666
(3) 2/327
(4) None of the above​

Answer 1

Answer:

option 4 or 3

I have some doubt

Answer 2

The distance the bullet moves in d)none of the above.

Explanation:

$m_{1}=5kg$

$m_{2}=5g$

$v_{2}=500\frac{m}{s}$

let the velocity of rifle=$v_{1}$

from conservation of law of momentum

$(m_{1}*0)+(m_{2}*0)=(m_{1}*v_{1})+(m_{2}*v_{2})$

$0=5vl+(5*10^{-3})*500$

$v_{1}=-0.5\frac{m}{s}$

velocity of rifle is $0.5\frac{m}{s}$

$v_{1}=\frac{s_{1}}{t}$

distance moves by rifle $(s_{1})=v_{1}*t$

distance covers by bullet $(s_{2})=v_{2}*t$

$\frac{s_{1}}{s_{2}}=\frac{v_{1}t}{v_{2}t} =\frac{0.5}{500}= \frac{1}{1000}$

$s_{1}:s_{2}=1:1000$