Hindu Achievements in Exact Science: A Study in the History of Scientific Development c13: VII. Kinetics
Hindu Achievements in Exact Science: A Study in the History of Scientific Development c13
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VII. Kinetics
c13.2
The Hindus analyzed the concept of motion from terrestrial and planetary observations. To a certain extent they approached, though, strictly speaking, they did not anticipate, modern mechanics.
c13.3
(1) Gravity: In astronomical works, e.g., of Aryabhata, Brahmagupta, and Bhaskara, the movement of a falling body is known to be caused by gravity. They ascribed gravity to the attraction exercised by the earth on a material body. But Newton's "law" of gravitation was not anticipated,
c13.4
(2) Acceleration: Motion was conceived as a change of place in a particle and incapable of producing another motion; but "the pressure, impact, or other force which produces the first motion produces through that motion a *samskara* or persistent tendency to motion (*vega*), which is the cause of continued motion in a straight line, i.e., in the direction of the first motion."⁵⁹ A series of *samskaras* each generating the one that succeeded it was also conceived. Acceleration is thus logically implied in the writings of Udyotakara, the Doctor of Nyaya (logic).
c13.5
(3) Law of Motion: The force of *samskara* (or persistent tendency to motion, i.e., *vega*) was known to diminish by doing work against a counteracting force; and when the *samskara* is in this way entirely destroyed, the moving body was known to come to a rest. Thus "*vega* corresponds to inertia in some respects, and to momentum (impressed motion) in others. This is the nearest approach to Newton's First Law of Motion,"⁵⁹ in the writings of Shamkara Mishra, the Doctor of Vaishesika (atomistic, Democritean) philosophy.
c13.6
(4) Accelerated motion of falling bodies: Prashastapada (fourth century, A.D.), the Doctor of Vaishesika philosophy, believed that in the case of a falling body there is the composition of gravity with *vega* (momentum) acting in the same direction from the second instant onwards. It is as if the two motions coalesced and resulted in one. "Here is a good foundation laid for the explanation of the accelerated motion of falling bodies; but Galileo's discovery was not anticipated as Galileo's observations and measurements of motion are wanting."⁵⁹
c13.7
Scientifically considered, Hindu ideas on statics do not seem to have made much progress. It is interesting to observe that among the Greeks statics was more developed than dynamics. This is the exact opposite of the state of investigation in India, where motion was probably understood better than rest.
c13.8
Thus the Hindus do not appear to have discovered the two celebrated principles of Archimedes (287-212 B.C.), viz.,
c13.9
(1) That relating to the equilibrium of bodies and centre of gravity as determined by the balance—the first principle of Statics: Those bodies are of equal weight which balance each other at equal arms of a straight lever.
c13.10
(2) That relating to the floating of bodies on liquids and the determination of specific gravity,—the first principle of Hydrostatics: A solid body, when immersed in a liquid, loses a portion of its weight equal to the weight of the liquid it displaces.