An object at rest will remain at rest and an object in motion will remain in motion at constant velocity unless acted upon by an unbalanced force.
Newton's Second Law of Motion
The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object. Force = Mass X Acceleration.
Newton's Third Law of Motion
Every action, there is an equal and opposite reaction.