Law 1: Law of Inertia- If it's not moving, it's not going to without effort. If it is moving, it won't stop- or change direction- without effort.  Make it enough!

Law 2: F = ma-

  If it just needs a small fix, use small force; if it needs a big fix, use big force. m is related to size and a relates to how big the change is. The bigger; the more effort required. 

 (and they are vectors- with both magnitude and direction!)

Law 3: Action-Reaction. If you apply a big force immediately, you get a big force opposite back.