There are three laws of motion given by newton, and thanks to him that a lot of understanding of physics became clear:-
1. Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it. [Rest or motion, and obviously acceleration is produced only by a force].
2. The rate of change of momentum is directly proportional to the net force applied on the body and in the direction of the force.
3.For every action there is an equal and opposite reaction.
See, these are the exact words by Newton [obviously translated in english xD] but you need to understand by your own as they are the basics of mechanics.
All the Best ! :-)