Explosions
Explosions can be viewed as collisions run backwards! Instead of Elost , we will need Esupplied by the explosion.
If you shoot a gun, there is a kick. If you hit a ball, there is a “kick” - if you swing and miss, you are out of balance since you expected a “kick” that didn’t come!
From Conservation of Momentum, we can see the reason for the “kick”: