ANSWER
Step-by-step explanation
To find the recoil velocity of the gun, we have to apply the principle of conservation of momentum:
Since the total momentum of the system (gun and bullet) is conserved and 0 before the bullet is fired, the equation changes as follows:
where m = mass of bullet = 4 g = 0.004 kg
M = mass of gun = 4.50 kg
v = velocity of bullet = 625 m/s
V = velocity of gun (recoil velocity)
Therefore, substituting the given values into the equation and solving for V:
The negative