A 4.0-kg meatball is moving to the right with a speed of 6.0 m/s directly toward a 2.0 kg meatball which is at rest. The two meatballs collide and stick together. What is their velocity immediately after
the collision?

Explanation:

The equation for this is the one for the Law of Momentum Conservation which says that the momentum before the collision of the balls has to be the same after the collision because momentum cannot be created or destroyed. For us in particular:

and filling in:

[(4.0)(6.0) + (2.0)(0)] = [(4.0 + 2.0)v] and

24 + 0 = 6.0v and

24 = 6.0v so

v = 4.0 m/s to the right

no. bullets are macro objects. wave nature is for light waves, extremely tiny particles. if a light particle was the size of your finger, the bullet would be the size of the universe. so basically, that huge difference in size makes the wave nature of matter insignificant.