MOMENTUM

===Momentum=== In order to simplify the behaviour of systems, Physicists look for conservation laws which link the before behaviour with a final state. Energy is the most common quantity stated as always being conserved (not quite true). This usually means that there is a quantity or number which is the same before and after. A very important quantity is momentum. The momentum of a particle is defined as the product of its mass and its velocity. Momentum is a vector. $$p=mv$$ Units are kgms^-1^ or Ns [image:http://i.imgur.com/xxM4CCf.jpg] From Newton’s second law, an unbalanced force acting on an object is equal to its rate if change momentum. $$F = \frac{dp}{dt} = m\frac{dv}{dt} = ma$$ F = ma is the familiar equation describing the action of unbalanced forces.