what did the first law state about the former reaction?
Newton's First Law of Motion states that objects continue to move in a state of constant velocity unless acted upon by an external net force (resultant force).
Force
Newton's First Law of Motion states that objects continue to move in a state of constant velocity unless acted upon by an external net force (resultant force). 
define unit of force using second law of motion UNANSWERABLE how does one define force? It is any interaction that, when unopposed, will change the motion of an object. who was the first to define it? The models regarding this were proposed by early thinkers which were corrected by Galileo Galilei, Sir Isaac Newton, and Einstein. where is the first person from? Pisa (then part of the Duchy of Florence), Italy. what is his profession? An astronomer, physicist and engineer. who was he married to? UNANSWERABLE when did he start his career as a scientist? After accidentally attending a lecture on geometry.
wiki:7714113
Force [SEP] First law
Newton's First Law of Motion states that objects continue to move in a state of constant velocity unless acted upon by an external net force (resultant force). This law is an extension of Galileo's insight that constant velocity was associated with a lack of net force (see a more detailed description of this below). Newton proposed that every object with mass has an innate inertia that functions as the fundamental equilibrium "natural state" in place of the Aristotelian idea of the "natural state of rest". That is, Newton's empirical First Law contradicts the intuitive Aristotelian belief that a net force is required to keep an object moving with constant velocity.