Newton's laws of motion are three physical laws that, together, laid the foundation for classical mechanical. They describe the relationship between a body and the forces acting upon it, and its motion in response to those forces. They have been expressed in several different ways, over nearly three centuries,and can be summarised as follows.
First law:When viewed in an inertial reference frame, an object either remains at rest or continues to move at a constant velocity, unless acted upon by a force.
Second law:The vector sum of the forces F on an object is equal to the mass m of that object multiplied by the accelartion vector a of the object: F = ma.
Third law:When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.