Derivative of the Volume of a Cone - Physics Forums
Nov 25, 2007 · The discussion revolves around finding the derivative of the volume of a cone, specifically in the context of related rates problems in calculus. Participants explore the …
What Exactly is Dirac's Delta Function? - Physics Forums
Aug 29, 2025 · In Dirac's Principles of Quantum Mechanics published in 1930 he introduced a "convenient notation" he referred to as a "delta function" which he treated as a continuum …
Suanpan & Soroban: History, Design, and Usage Guide
Jan 19, 2019 · Introduction Overview Abacuses are commonly seen in ancient civilizations around the world as a convenient tool for simple calculations. In this article we focus on the traditional …
Light & Time • Physics Forums
Feb 11, 2026 · Not a great question but I heard someone say that time does not move for a photon. T=0. So therefore both its Emission &Absorption are simultaneous events. I say no. If …
Feynman's bug (hot plate) in generality • Physics Forums
Feb 13, 2026 · A textbook (in German language: Sexl-Urbantke, Gravitation und Kosmologie) says that intrinsic curvature of spacetime is a definition. The alternative is to postulate a flat …
Why is ##(t_1'-t_2')^2## constant in proof(invariance of intervals)?
Mar 11, 2025 · What do you mean by "constant"? It's the difference in time coordinates of two events, so of course it doesn't change. But I don't think that's what you mean.
Are Maxwell's equations linearly dependent? • Physics Forums
May 15, 2024 · The discussion centers on the linear dependence of Maxwell's equations in their microscopic or vacuum formulation. Participants explore the implications of the equations in …
Thrust Bearings and Smooth Journal Bearings reaction moment?
Sep 6, 2017 · The discussion revolves around the presence of reaction moments in thrust bearings and smooth journal bearings, as referenced in R. C. Hibbeler's textbook on …
Is a Cusp Considered an Inflection Point in Calculus?
Mar 23, 2011 · is a point only considered an inflection point if a tangent (whether vertical or not) exists or just whether just that f(c) is continuous suffices. For instance, is a cusp/corner point …
What Does Azimuthal Symmetry Mean in Physics? - Physics Forums
Oct 25, 2014 · Azimuthal symmetry in physics refers to a system's invariance under rotation around a specific axis, typically the z-axis. This concept is defined mathematically by the …