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...
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...
Suppose somehow an object is moving upwards with a speed ##v##, at this point I start applying a force ##F## that is equal to its weight, so the net force on the object is zero. So it will continue moving upwards with its initial speed. Suppose after the height difference is ##h##, I stop...
On the first attempt I used conservation of energy to get it down to a single equation involving theta and v (the speed when the angle is theta). But I had no idea how to find v.
Now since the maximum speed is given, it is possible to find the maximum angular displacement, ##\alpha##. Then...
Sorry it was late at night and I didn't expand on it. I've thought about it a bit more and it comes down to this: You can move around forces (not changing their direction of course) as long as they still act on the body, and then the body's translational motion won't change. However moving...
Ok so putting it all together (for now):
1. I found this: https://www.damtp.cam.ac.uk/user/po242/pdfs/Mech2015/L2.pdf, might be helpful to any viewers.
2. In these sorts of problems, you cannot move around forces willy nilly.
3. As a consequence of (2), any lines of action of any two...
Isn't your first equation derived under the assumption that the centripetal acceleration is ##\frac{v^2}{r}##? But that's only true when there's no tangential acceleration, which is not the case here.
Edit: Ok I suppose that the total acceleration vector can be resolved into two components: the...
Are lines of action 'fixed' in space? Because if not, I can just move the point of intersection which would, I assume, prohibit me from showing the desired relation of the tangents of the angles.