Newtons first law is that if an object is in motion it will stay in motion and if a object is at rest it will stay at rest unless acted upon by a external force
when the bus hit the car the car was at rest but then the bus was a external force that made it go into motion
newtons second law is that objects will move faster and farther when given more force
if I was to get some friends and push the cop car it would move further with more acceleration
newtons third law is that every action has a equal and opposite reaction
when i push the gas it is my action then the car reacts and accelerates