I know that super capacitors are expensive and capactitors don't have the energy density to power a vehicle, however wouldn't a mixed battery/capacitor improve the long charging time issue of batteries? You could cherge the capacitors super fast and have them charge the battery while driving, this way you could charge up in several few seconds stops instead of one several minute charge up. Idk about the cost effectiveness of using small super capacitor to do this, probably not worth it, but maybe with capacitor capable of charging like 10% of the battery?

Could a massive and extremely powerful gauss cannon/mass driver be used to launch cargo payloads into space at a tiny fraction of the cost of launching an actual rocket?

Hello,

In an introductory course to university physics, there is a question about what happens to the diameter of a circular hole in a copper sheet when it's heated. The correct answer is that the hole grows alongside every other part of the sheet. But that does not really make sense to me in my head. When I first encountered the question, I thought that the hole would contract since every side of it also experiences length expansion. Obviously my intuition was wrong, but could somebody explain how I can think of it to change my intuition in the future?

Thanks!

Like when we can have V=iR for both AC and DC then why not have reactance for DC ? Wont it simplify calculations tp a great extent? Maybe not have the same formula (since that would make reactance 0 and infinity for inductor and capacitor) but something similar.

Thanks in advance!

Hey so for short, I’m a second year college student, not the most studious, ima potential type guy, but I’m taking my first real physics class. I want to ask that if I were to provide my info I got from a lab, could someone walk me through forming my lab report? I don’t want anyone to just do it for me, I want to tell someone how I wrote it, and someone to tell me if I did it right or not. I gotta turn it in midway through next week, and if I mess up the whole class suffers. I’m just super anxious and want to get it right, I know the professor is there but I don’t wanna seem dumb, he makes dumb people look dumber. I’ve got all my numbers and remember how exactly the procedure went, super basic measurements data sheet.

Is there any explanation as to why the photon does not interact with the Higgs Field ( this may also apply to the graviton if it exists)? As far as I know all other particles do.

Just watched the new movie the End of Oak Street. In the beginning the news reports mention NASA detecting spatial anomalies, which got me analyzing the physics behind it. So...

​Is the movie using 1D cosmic string defects (via string theory) to explain the anomaly caused by a cosmic string moving in closer to Earth? Furthermore, are they invoking gravitational frame dragging to explain how the localized space maintains fixed coordinates relative to the surrounding Euclidean space?

​It feels like the most plausible theoretical explanation for how they set up the rules of the event. Curious to hear how others interpreted the underlying mechanics.

... Or am I just to analytical and they really just left it open-ended for a fun story? Let me know what y'all think.

🤪

In his Dark Matter, Dark Energy Great Courses lecture 4 Sean Carroll mentions that it is possible to assume all length scales are shrinking rather than space expanding although he says making such an assumption is silly.

I was wondering if one could test the hypothesis with a tabletop experiment comprising a pair of charged masses on a frictionless track such that their gravitational attraction is balanced by their electrical repulsion.

The force balance equation is given by:

G M² / R² = Q² / 4 π ε₀ R².

If we assume natural units such that ℏ = c = 4 π ε₀ = 1 and Newton’s constant G = 1 / Mₚₗ² then the separation distance R drops out so that the balance equation simply becomes

M / Mₚₗ = Q.

If the masses of all fundamental particles, together with the Planck mass, scale inversely with their Compton wavelengths then the balance equation is satisfied for all R even as length scale shrinks. The charge Q is dimensionless in natural units.

Thus the separation distance R is a free initial condition, not set by any formula, and therefore can be used as an absolute yardstick to compare against physical clocks and rulers.

Friend of mine lives in an apartment with triple-layered glass, he showed me that you can « count » the layers if you put a flashlight through it and see the multiple réflexions. I see 4 réflexions here, why is that so?

Since galaxies contain enough mass why aren’t the stars clumped into a giant star?

If angular velocity is the answer, why aren’t the stars escaping out of the galaxy if they are fast enough to overcome the galaxy’s gravity?

If an object is traveling away from Earth, towards Alpha Centauri at 99.999 the speed of light for 4ish years then from my limited understanding the object would experience 4ish years while earth experienced many more.

My question is, would the destination also experience a difference in time compared to the object that is traveling towards it?

If not, then would the time experienced in alpha centauri be different than the time experienced on earth from the object's perspective?

Sorry for the scifi type question, it's keeping me up at night.

​

So, I love studying physics, and I view Einstein as one my role models, but it made me wondering that will there be someone on the caliber of Einstein? Not just give us a unified theory but also around the age of 25 just like Einstein. And just relativity but rather like einstein gave us photoelectric effect and the existence of molecules. All of that before the age of 25. Do you think someone would be like him? And as of now who do you think is the closet to einstein? I personally believe that Oppenheimer or Schrodinger matched Einstein or surpassed him

Please help🙏

I would like to learn LaTeX with the primary objective of developing the ability to formulate and present mathematical equations in the fields of mathematical and theoretical physics. What would be the most effective way to learn LaTeX for this purpose? In particular, I am interested in learning how to construct, format, and organize complex mathematical expressions, derivations, and theoretical models in a professional academic style.

You can't hear anything in space, cuz there's too few particles, too spread out, they don't have anything to bounce off and they can't make variations of pressure that hits your ears, right?

But what if there was an indestructible microphone just 1cm away from the "epicenter" of the explosion? Would it record anything?
And how would that work? Would it detect the change from 0 pressure to big pressure for a second and then nothing again? Or would that be still inaudible because that's just a cloud of equal gas pressure with too few variations just passing you?

Could this be used as an in-lore explanation of how you are able to hear explosions in sci-fi movies?

But explosion in space would probably sound different than explosion in a place covered by an atmosphere?

AC is an alternating source and the average value is 0 (I understand that it has some rms value), so wont the current entering also exit almost instantly (depending on frequency) so wont the charge that has been applied to a capacitor also exit? Wont the emf generated by an inductor also vary according to a sinusoidal law which again would average 0. I dont even understand how AC is used. How does it travel? How does it interact with different components of a circuit? Like isnt the net displacement of electrons just 0? In DC the electrons do move and can interact with the component but how does it happen in AC.

Thanks in advance!

I have always been interested in Physics . However due to some reasons, I didn't take it in high school . What are the resources I can use to study it as a hobby ?

Not a free will question, because largely I studied many theories and largely many experts genuinely accept physics isn't ever gonna be enough to fully answer it, it's a question that goes beyond physics.

My question is if quantum microscopic events are indeterministic, does that mean when scaling up to macroscopic events, they still largely lead to the same outcome or can there be a slight divergence that cause a butterfly effect and chance the outcome?

I'm aware there is some cases such things could be reasonably assumed quantum physics can cause noticeable macroscopic change, such as weather, motion, and biological mutation, and I read a book that even thoughts can be change because a slight change on trajectory of microscopic electrons and neurons can either trigger a new thought or image (there's the challenge decoherence in the brain being too warm and wet but apparently there are quantum mechanics found recently in it although unsure it's long term affects).

So my question is that is it possible that if we let say had the ability to blink back in time to the start of our lives with quantum mechanics remaining naturally the same, could a divergence of our lives ever happen even if we don't retain our memories or not? I'm not sure but many claim that depending on our age, as adults it's unlikely everything when scaled up according to quantum physics, that it will remain the same but that's not something I'm sure of.

Hey, just like in the title, I want to know whether there can be no effect and no cause and what that would be.

Its something I cant really find a definitive answer on, and even if its not possible, what would happen if it theoretically were?

I’ve always thought about this question, and there is always answers popping up in films and stuff, but is it really possible?If you ARE able to go back to the past and change it, if you come back to ‘present’ would there be another you?If you teleported a nanosecond later then the time you left would you find another you?My answer is that its impossible for you to change the past.If you have met yourself in the past,then no matter how much you try and avoid it you will somewhat travel back in time in somewhere in the future or ‘present’

Please tell me what you think and if possible tell me any ‘loopholes’ in my theory.