Question

A gun of mass 1000 kg fires a shell of mass 2 kg with a velocity of 200 m s-1 calculate the velocity of recoil of the gun

Answer 1

since no external force acts on the system of gun and shell

thus linear momentum will be conserved

1000*v+2*200=0+0

v=-0.4 m/s

Answer 2

since no external force acts on the system of gun and shell  

thus linear momentum will be conserved  

1000*v+2*200=0+0

v=-0.4 m/s