# Who came up with the laws of conservation of momentum?

Who came up with the laws of conservation of momentum? I'm more specifically interested in the conservation of angular momentum.

• Hi, you might want to have a look at this page to improve your question: hsm.stackexchange.com/help/how-to-ask – VicAche Jun 27 '15 at 17:02
• Angular momentum isn't momentum. – Ben Crowell Jun 28 '15 at 12:12
• Considering that angular momentum isn't momentum, this is really two questions in one. Also, you really should add some research to show your efforts, as explained in the link provided by VicAche. – Cicero Jun 29 '15 at 14:17

As to the first part of your question, conservation of momentum comes directly from Newton's Laws, so technically Newton himself came up with conservation of momentum, and others followed Newton's logic to notice that in certain scenarios that other conservation conditions exist (energy, angular momentum, mass, etc).

Descartes wrote in *Le traité du monde et de la lumière *:

…when one of these bodies pushes another, it cannot give the 2nd any motion, except by losing as much of its own motion at the same time… (AT, XI, 41)

Motion being "le transport d'une partie de la matière, ou d'un corps" this is probably the first enonciation of the conservation law for linear momentum. The book was published in 1664, some 30 years after it was written, and meanwhile the Principles of philosophy published in 1644 stated:

Lorsqu'une partie de la matière se meut deux fois plus vite qu'une autre, et que cette autre est deux fois plus grande que la première, nous devons penser qu'il y a tout autant de mouvement dans la plus petite que dans la plus grande ; et que toutes fois et quantes que le mouvement d'une partie diminue, celui de quelque autre partie augmente à proportion.

Introducing a more refined "quantity of movement" the book however stated some erroneous propositions.