Discussion Overview
The discussion centers around the historical definition of angular momentum as the cross product of position vector and momentum vector (r x p). Participants explore the origins of this definition, its validity, and the implications of angular momentum in physics.
Discussion Character
- Debate/contested
- Historical
- Conceptual clarification
- Mathematical reasoning
Main Points Raised
- Some participants inquire about who first defined angular momentum as r x p, with references to Newton and Aristotle.
- Others argue that the modern concept of vectors and the cross product was not developed until the mid-1800s, suggesting that earlier figures like Aristotle and Galileo did not use this definition.
- A participant expresses skepticism about the validity of the definition, citing an experiment where r x p is not conserved without external torque.
- Some participants discuss the relationship between linear and angular momentum, with one suggesting they are fundamentally the same, while others assert they are distinct with different conservation laws.
- Concerns are raised about the interpretation of forces acting on objects in circular motion, particularly regarding how forces affect velocity and angular momentum.
- One participant claims that physics textbooks incorrectly teach angular momentum as mr^2w, proposing an alternative definition for point masses as mrw.
Areas of Agreement / Disagreement
Participants express differing views on the historical origins of the definition of angular momentum and its validity. There is no consensus on who first defined it or on the correctness of the definition itself.
Contextual Notes
Participants reference various historical figures and concepts, indicating a lack of clarity regarding the origins of angular momentum as r x p. There are also unresolved questions about the implications of angular momentum conservation and the relationship between linear and angular momentum.