Momentum, Work and Energy Michael Fowler, U. Va. Physics
In 530 A.D John
Philoponus in his commentary to
Aristotle’s physics developed a concept of momentum. Aristotle used the example
of a thrown ball must be kept moving by something which was the motion of the
air had claimed that everything that is moving must be kept moving by something
Aristotle’s theory was accepted until the time of Galileo,
but a few were skeptical.
Philoponus pointed out that it was difficult to believe Aristotle’s
claim that motion of an object is promoted by the same air that is resisting
He proposed instead that a force was imparted to the object
in the act of throwing it.
Ibn Sina published his own theory of motion in The Book of
Healing in 1020 by Ibn Sina he published his own theory of motion. He agreed
that a force transmits to the object by the thrower – but unlike Philoponus,
who believed that it was temporary, and would decline even in a vacuum –but it
was viewed differently by Ibn Sina who viewed it as a persistent. He understood
that it required external forces such as air resistance to dissipate it.
The European philosophers Peter Olivi and Jean Buridan
refined these ideas. in about 1350 Buridan was made rector of the University of
Paris, referred to momentum as proportional to the weight times the speed.
Like Ibn S?n?, Buridan held that momentum would not go away
by itself; it could only dissipate if it encountered air resistance, friction,
René Descartes believed that the total “quantity of motion”
in the universe is conserved: quantity of motion = size and speed. But this
equation is not specific because Descartes didn’t distinguish between mass and
Leibniz, in his “Discourse on Metaphysics”, gave an
experimental argument against Descartes’ idea of “quantity of motion”.
Leibniz dropped blocks of different sizes, different
He found that size x speed did not yield a conserved
The first correct statement of conservation of momentum:
English mathematician John Wallis, 1670
Mechanica sive De Motu, Tractatus Geometricus:
Isaac Newton’s Philosophiæ Naturalis Principia Mathematica,
Defined “quantity of motion”, as “arising from the velocity
and quantity of matter conjointly”
-> mass x velocity – which identifies it as momentum.