Physics Forums Insights

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Scientific physics forums for professionals and students to discuss serious issues and topics regarding physics in theory, practice, study and reality. Students can also find help for homework and career perspectives

Physics Forums Insights

2w ago

PBS Space Time produces some very good videos on the foundations of quantum mechanics (QM), so let me comment on their video What If Physics IS NOT Describing Reality to provide (crucial) missing information. This comment pertains only to the first 9 min of the video, i.e., it has nothing to do with “entropic uncertainty ..read more

Physics Forums Insights

1M ago

Abstract It took until the last century for physicists and mathematicians in the Netherlands to question the Euclidean concept of dimension as length, width, and height. Luitzen Egbertus Jan Brouwer published a ground-breaking paper On the Natural Concept of Dimension (Amsterdam, [2]) in 1913 about the mathematical definition of dimension picking up a thought from ..read more

Physics Forums Insights

4M ago

The concept of quantum superposition (or superposition for short) is very counterintuitive, as Schr##\ddot{\text{o}}##dinger noted in 1935 writing [1], “One can even set up quite ridiculous cases.” To make his point, he assumed a cat was closed out of sight in a box with a radioactive material that would decay with 50% probability within an ..read more

Physics Forums Insights

4M ago

The slinky drop is a rather simple experiment. In its most basic form, it requires only a popular toy for children, a stable hand, and a keen eye. For a better view, using a modern smart phone to capture a video of the experiment also helps to capture the falling slinky. Apart from the commonly ..read more

Physics Forums Insights

6M ago

Introduction The figure on the right shows a “double-double” Atwood machine with three ideal pulleys and four masses. All pulleys are released from rest simultaneously. Which of the choices below describes the angular motion of the top pulley P after some time has elapsed and why? It rotates clockwise with increasing angular speed. It rotates ..read more

Physics Forums Insights

7M ago

A division by zero is primarily an algebraic question. The reasoning therefore follows the indirect pattern of most algebraic proofs: What if it was allowed? Then we would get a contradiction, and a contradiction is the greatest enemy of mathematical rigor. Many students tried to find a way to divide by zero once in their ..read more

Physics Forums Insights

8M ago

Introduction This elaborates some of the claims in my insights article on digital audio. The Sinc Function The first link in my insights article has a section on filters, but I will detail the most critical case. The bit depth is assumed to be so large for all practical purposes that it is infinite, and ..read more

Physics Forums Insights

8M ago

Introduction First, we need some background in Digital Signals. This can be mathematically quite advanced, but since I would like this article to be accessible to as wide an audience as possible, here is a link that explains what is needed (not even Calculus is required): https://brianmcfee.net/dstbook-site/content/intro.html An important point not emphasised in the above ..read more

Physics Forums Insights

10M ago

Introduction Series play a decisive role in many branches of mathematics. They accompanied mathematical developments from Zeno of Elea (##5##-th century BC) and Archimedes of Syracuse (##3##-th century BC), to the fundamental building blocks of calculus from the ##17##-th century on, up to modern Lie theory which is crucial for our understanding of quantum theory ..read more

Physics Forums Insights

11M ago

Abstract I remember that I had some difficulties moving from school mathematics to university mathematics. From what I read on PF through the years, I think I’m not the only one who struggled at that point. We mainly learned algorithms at school, i.e. how things are calculated. At university, I soon met a quantity called ..read more