[Potironette]

Sadly, I've never learned dot product, so I'm not sure what the square brackets mean D:, but it does look useful.


I'm reviewing a question that essentially tells me about a cannon firing a cannonball, and that before it fires, the momentum of both the cannon and the ball together is 0. Therefore, after it fires, the momentum of the cannon and the ball should make 0 again..but I can't seem to remember a logical reason for why that is.

EDIT: Random question - is it a more useful habit to label things like the cannon and cannonball m_1 and m_2 or m_cannon and m_ball ?

EDIT2: struck out question about momentum before and after. I suppose it's basically the same as momentum is conserved, therefore, if two things are at rest and suddenly move because of each other, momentum is still conserved therefore their total momentum added together is 0?