IOSR Journal Of Applied Physics (IOSR-JAP) e-ISSN: 2278-4861.Volume 13, Issue 2 Ser. I (Mar. – Apr. 2021), PP 61-137 www.Iosrjournals.Org DOI: 10.9790/4861-13020161137 www.iosrjournals.org 61 | Page Newton’s generalized form of second law gives F =ma Ajay Sharma Fundamental Physics Society. His Mercy Enclave, Post Box 107 GPO Shimla 171001 HP India Abstract Isaac Newton never wrote equation F =ma , it was clearly derived by Euler in 1775 ( E479 http://eulerarchive.maa.org/ ). Also, Newton ignored acceleration throughout his scientific career. It must be noted that acceleration was explained, defined and demonstrated by Galileo in 1638 (four years before birth of Newton) in his book Dialogue Concerning Two New Sciences at pages 133-134 and 146. Galileo defined uniform velocity in the same book at page 128 and applied it in Law of Inertia at page 195 in section The Motion of projectile. Descartes in book Principles of Philosophy (1644) and Huygens in his book Horologium (1673) used uniform velocity in defining their laws. Huygens also applied gravity in 1673 i.e. 13 years before Newton. Newton also defined first law of motion in the Principia (1686,1713,1726) in terms of unform velocity. Galileo, Descartes and Huygens did not use acceleration at all, as uniform velocity is used in law of inertia. Likewise, Newton ignored acceleration completely, even it was present in literature during his lifetime. So, it is distant point that Newton gave F=ma. The geometrical methods were the earliest method to interpret scientific phenomena. Now there are three main points for understanding of second law. Firstly, genuine equation based on second law of motion F =kdV (it is obtained like F =Gm 1 m 2 /r 2 or F  m 1 m 2 , F  1/r 2 or F  dV) . But F = kdV is neglected by scientists completely . Secondly scientists related F =ma with second law. Then they tried to obtain, F =ma from second law, but it is not obtained from it. Thus, scientists made arbitrary assumptions that motion is momentum (mV), in fact motion is velocity. It does not serve the purpose. Then scientists assumed that change in motion (momentum) is equal to rate of change of momentum. As both sides of equation have different units, dimensions and magnitudes so these arbitrary assumptions are completely inconsistent. Thirdly to obtain F =ma from second law of motion is to change definition of the law so that acceleration appears in it. However, Newton has completely neglected acceleration. But now acceleration is arbitrarily brought in second law. The definitions of first and third laws of motion are quoted in the text books and standard references in the same way as given in the Principia. W W Rouse Ball has changed definition of second law of motion slightly i.e. used phrase change in momentum per unit time. Disagreeing with this I. Bernard Cohen given 4 equivalent equation forms of second law of motion. F =ma is inseparable part of physics, so it can be it can be obtained by changing the definition of the law, “The rate of change of momentum with time is equal to the motive force impressed; and is made in the direction of the right line in which that force is impressed. ” Thus, we get F =ma from modified form of law, not from original form. --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 18-03-2021 Date of Acceptance: 01-04-2021 --------------------------------------------------------------------------------------------------------------------------------------- I. Early Physics Gradually ancient minds tried to resolve various mysteries observed around him. There was no short cut, all processes took their own time. First feeling in human mind may be fear of some power which was beyond human’s physical and mental control …. thus religion was developed in different ways in different regions. But eventually should converge at same point, so it must be cohesive force and not divisive. Earlier all branches of knowledge were fused together. The explosion of knowledge may be compared with ‘big bang’ which took place gradually and slowly. In ancient days man started expressing his insights on the sand or earth with diagrams, thus geometry was first mode of expressions. The science came into being, something we understand and also make others understand repeatedly. The converse is superstition, we cannot understand, cannot make others to understand. Initially all branches had one name, the natural philosophy. Natural philosophy was the philosophical study of nature and the physical universe that was dominant before the development of modern science. The various scientists extracted various branches such as mathematics, physics, chemistry, biology etc. emerged from natural philosophy. In physics Newton, Galileo and Aristotle were the pioneers, and numerous others who brought physics to current status. Earlier Aristotle (385-323BC) stated that force is required for movement of body. The table stops as soon force (may be push or pull) ceases to act on it. It is clearly observed even now due to presence of various resistive forces. The concept of inertia was alien to the physics of Aristotle. Aristotle, and