May 30th, 2010 
admin We know that the most basis physical quantities are length, mass and time.
From here, we’ve defined velocity, acceleration, momentum, force, energy, power, intensity, and so on.
Momentum of a substance is defined as product of mass and velocity of the substance.
But I didn’t see any relationship to say that momentum is always conserved. It’s just a rule, but how this rule come from?
For conservation of energy, I know, is just an ability to do work. So, the idea is energy cannot be created or destroy. Here’s how conservation of energy comes from. But what about conservation of momentum?
Thank you.
