Recent content by DrBanana

I asked the same question here: https://www.physicsforums.com/threads/conceptually-understanding-change-in-potential-energy-with-0-net-work.1062154/ Plus there is a three part series on the pitfalls of the work-kinetic energy theorem on the Insights blog, that might illuminate some things as well.

Your answer seems interesting but unfortunately I made this post as a precursor to understanding springs : (

But how can we know (without experiment) that that assumption is true?

So, is there a deeper reason behind this, or is it just taken to be true (as in, do we only conclude this because assuming the opposite case would contradict calculations and reality)?

An alternative title could have been "how do forces propagate" but google searches bring up things related to waves only. Initially my problems started with a mass on a spring but I was able to boil it down to any general system comprising at least two 'parts' in succession. Suppose you have...

This isn't really a question per se, but it recently just 'clicked' for me and I would like to share what made that do so. There are dozens of threads answering this question, but in my opinion most (but not all; there are some good threads on this forum, I just want to show how I came to...

I think there was a line in my textbook that went something like "because these two charged spheres have different potential, current will flow if they are connected by a wire (until the potentials get equal again)." And there must've been a more general claim in the lower grades.

For the future viewer I found this: https://physics.stackexchange.com/questions/410402/why-the-current-doesnt-flow-in-an-open-branch Sorry I didn't find it before, it didn't come up in my googling. Does current not flow at all, or does it flow for a short period of time when this circuit is...

I know that a voltage difference doesn't necessarily imply current flow, but all the explanations I seem to find of that either say that that happens because the resistance is infinite, or there is nothing connecting the two points in question (the two are basically the same thing, as I...

Sorry for the overly general title but my problem is regarding a specific problem: find the net force on the bob of a pendulum as a function of ##\theta##, the angle it makes with the vertical (assuming the observer is stationary with respect to point from which the string is hung and the...

I can't answer your question as I don't know much about this myself. However as far as I know, this is Einstein's second postulate for special relativity, and you don't really prove postulates (I might be wrong). Also take caution of any explanation that uses the Lorentz transformations, since...

I know this wasn't the topic of the post, but what if this action-reaction pair is not a conservative force?

Haven't read it but for the benefit of the potential viewer, I found this: https://archive.org/details/natureofthermody031258mbp/mode/2up It is by Percy Bridgman, a physicist who seems to have worked on this stuff.

First of all I thank both you and @Dale; the answers are really satisfying to read. My takeaway from yours (in the first case) is that while gravity is a force which is doing work, it is a force of different mathematical nature, and every time we encounter it, we should not think of the work...

I was sort of suspecting this. So one can say, the energy getting stored in a system is equal to the energy flowing in; some of this energy might manifest itself in kinetic energy of a part of that system, if it can be shown that net work was done on that part of that system, and the rest is...