Question

A gun of mass 5 kg fires a 50 g bullet with a velocity of 200 m/s. What is the recoil velocity of the gun.?

Answer 1

Let mass and velocity of ball be m1=0. 05kg and velocity v1=200m/s.  

Let mass of gun be m2 = 5kg and recoil velocity be v2  

Use conservation of momentum.  

m1 v1 = m2 v2  

(0.05)*(200)=(5) v2  

V2=2m/s.

Answer 2

The "recoil velocity" of the gun is 2 m/s.

Given:  

Mass of the gun = 5 Kg

Mass of the bullet = 50 g

Velocity of the bullet = 200 m/s

To find:  

Recoil Velocity = ?

Solution:

By Law of Momentum Conservation, momentum remains conserved.

$MV+mv=0$

Where,

Mass of bullet: m

Velocity of bullet: v

Mass of gun: M

Recoil velocity: V

On substituting the values on the formula, we get,

$MV+mv=0$

$(5000 \times V)+(50 \times 200)=0$

$V = -2 \ m/s$

The “-” sign indicates the velocity of gun is in the opposite direction of the bullet.