Statement

A competitor shoots a plate by using a rifle of 2,5 Kg on a skeet shooting competition. Knowing that the ball is 23 g and it is shot horizontally at 350 m/s, what is the recoil of the rifle?
Solution
Data
mass of the rifle |
velocity before the shot |
velocity of the rifle after the shot |
mass of the bullet |
velocity of the bullet before the shot |
velocity of the bullet after the shot |
Resolution
If we consider the bullet and the rifle as a system, the outer forces to it are cancel since, initially, both are held by the handle, therefore the conservation linear momentum principle, momentums before the shot () and after the shot () are the same:
For this reason we are going to calculate the linear momentum of the system at that time, having into account the momentum of a system is equivalent to the sum of momentums of the bodies separatly:
Momentum before the shot | |
Momentum after the shot |
Matching both linear momentums and solving for , we can calculate the rifle´s speed of recoil after the shot.