Question

a bullet of mass 25g is fired from a rifle of mass 2 kg imagine that no other force are acting on a the system if a bullet travels with a velocity of 2m/sec what will be the velocity of recoil of rifle​

Answer 1

Explanation:

Ignoring the fact that a 2m/s bullet is comically slow (and quite heavy at 25g) and the slowest speeds of glacial subsonic ammo are over 200m/s, the easiest way to do simple momentum calculations like this is using P=mv, that is momentum = mass times velocity. The momentum of the two are equal and opposite according to our late friend Isaac Newton, so 25g * 2m/s = 2000g * 0.025 m/s.

So the speed the rifle moves at is 0.025 m/s.