Sir Isaac Newton’s three laws of motion, published in his thesis Philosophiæ Naturalis Principia Mathematica (Latin for Mathematical Principles of Natural Philosophy) in 1687, are what modern-day physicists and metrologists refer to when they describe force as any interaction that, if unopposed, will change the motion of an object. Newton’s first law states that objects continue to move in a state of constant velocity unless acted upon by an external net force or resultant force. Newton’s second law builds upon the first by establishing the vector equation: that the momentum of the system is the net (vector sum) force. Finally, Newton’s third law posits that all forces are interactions between different bodies; and that 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.
In manufacturing, force is a quantity on which many other quantities such as torque, thrust, and pressure are based. According to the National Institute of Standards and Technology (NIST), accurate force measurements are required in many applications to “determine the strength of materials, quality control during production, and consumer safety,” among other purposes.