NEWTON’S SECOND LAW OF MOTION, F=MA; EULER’S OR NEWTON’S?

Objective: F =ma is taught as Newton's second law of motion all over the world. But it was given by Euler in 1775, forty-eight years after the death of Newton. It is debated here with scientific logic. Methods/Statistical analysis: The discussion partially deals with history of science so various aspects are quoted from original references. Newton did not give any equation in the Principia for second, third laws motion and law of gravitation. Conceptually, in Newton's time, neither acceleration nor second derivative was employed, so it was impossible for him to write F =ma. Descartes laws preceded Newton's laws; these aspects need to be taken in account. Newton separated physics from natural science. Findings: The Principia's second law at pages 19-20 states as– the alteration in motion is proportional to force i.e. F = (v - u). In the existing literature, motion is regarded as ‘quantity of motion' (amount or quantum or magnitude of motion). Furthermore, ‘alteration', i.e. difference, is regarded as ‘rate of change of '. These are not scientifically justified. F = (v-u) is not taught and mentioned anywhere, however Euler's F=ma is regarded as Newton's second law of motion. If Proposition 1, Proposition VI and Proposition LXVI are critically analyzed, then F = ma does not follow from them in any way. Before Newton' time , tradition of representing change in velocity by length of segment is never justified. F=ma can never be derived from circular motion as it describes linear motion. More over laws are based on scientific logic not on traditions. Further law of gravitation was given in nearly 12 propositions and was not pointed as product of masses of bodies. The concept of units and dimensions was initiated by Fourier in 1822 i.e. 136 years after publication of the principia. Application/Improvements: The credit of discovery of F =ma must not be given to Newton. Newton started beginning of physics by defining new terms, but the beginning must not be regarded end.