I am not a physicist. But I've been loosely following the string theory drama. What's your take on Leonard Susskin saying that we need to start over in physics after ~55 years of string theory? It seems there have been many dissenting voices or possible theories that have fell to deaf ears in that community because of the vice grip string theory has had. He was recently on Curt Jaimungal's podcast. Seems wild to work on something for so long to then say it's not the way anymore while simultaneously being ignorant to others' proposed work. Idk, jah bless.

Background: I am working on a game recently. In some scenes of the game, we will sprinkle water from the side of container's bottom. For simplicity we use constant speed of water sprinkling, i.e. water "leaked" volume will be proportional to time, which means the water is leaking at constant speed.

But I know this model is simplified, since the bottom's water pressure will change when water becomes little and little in there. And I am wondering, from real-world physics, how leakage speed (cubed meters per second) is linked to height of water in container?

And I worked a little bit myself. Well, I have limited physics knowledge up to high school level. And my conclusion is: the leakage speed is proportional to the square root of height of water, and here is my solution.

Solution's screenshot

Please correct me if I did something wrong.

I’m curious

As an aside, the static/kinetic coefficient model is actually pretty lousy. It works as a way to set up problems forcing students to deal with the vector nature of forces, and allows some simple qualitative explanations of observed phenomena, but if you have ever tried to devise a lab doing quantitative measurements of friction, it's a mess.) from https://physics.stackexchange.com/questions/541/can-the-coefficient-of-static-friction-be-less-than-that-of-kinetic-friction#:~:text=What%20would%20it%20mean%20to,instant%20the%20object%20started%20moving.

My imagination is not enough to understand the uniform expansion of the universe in which there is a monstrous force of gravity, attracting stars to itself, but not able to slow down the expansion of the universe. And also why it does not work in our solar system, we are as if one whole and everything is expanding around us, but not in our solar system. Help

I have a pole that is a light year long, I am at one end of the pole and there is a light switch and light bulb at the other end of the pole which I can see with a very good telescope.

I push the pole causing it to hit the light switch and turn on the light. How long does it take for me to notice the light turning on after I push the pole into the light switch?

Is it possible that the universe is expanding locally but the expansion is only observable at large scales as a cumulative effect?

I'm a high school student and I'm done with all of my college applications, but I still need to pick a major for some of my colleges since they don't have undecided options. I recently read The Elegant Universe and enjoyed it a lot. My school does not offer AP Physics, but I enjoyed my honors physics class well enough. Because of all that, and because I'm decent at math but don't want to be an engineer, I was thinking of putting physics down as my major choice. I just don't know how much this stuff is a predictor of enjoying the actual major, or if I should stick to reading pop physics.

I don’t fully understand the flow of imaginary time. If imaginary time exists, is it possible to intervene in it? Because this wouldn’t affect our past and wouldn’t contradict physical laws, right? But would this cause decay in an alternate universe?

People tend to say, that you can't feel the acceleration from the force of gravity because it's not the force, but only the normal force from the floor when you hit it because that is a force.

I don't think you could feel any force if it was applied uniformly on you even if it's a real force. Imagine you get charged, and and electrostatic field switched on, or a magnet turned on while you were moving. If you were uniformaly changed you would probably not FEEL any force acting on you, just like gravity.

The only way to feel a force is if it's not uniformly applied, like a floor only hitting your feet. That causes a compression that you then feel. If you were just pulled on uniformly everywhere, there would be no compression to feel. If you get pulled by a rope, you also only feel a compression cause from the rope being only attached to one point on your surface.

I think there isw ont way to actually feel a force pulling on you, and that's only if the force has a gradient over your body. And that could happen with any force, with gravity it's called spaghettification, but you could feel this with those other forces as well.

I was sick the day we covered this in class

like Is it ALWAYS 0 at the top of a vertical circle? I also don’t understand if it’s 0 when you’re going at max speed, and if it is 0 when youre at max speed, why?

If we have a light wave propagating in 3D then it oscillates perpendicularly to its direction of travel. Is this just a property of nature/a mathematical consequence of Maxwell's equations or is there a more fundamental reason for why the light wave can't oscillate longitudinally?

While we're also on this topic, what does it mean in 4D for a wave to be polarized in its time direction? I can't visualize what such a wave would look like.

a = 4s - v

How to find position - time graph of this function?

In 3D one can easily check if a force is conservative by computing its curl (thanks to the Stokes's Theorem, which only works in 3D).

Is there any generalized way of knowing if a vectorial force in 'd' dimensions is conservative?

What if we were to work in a general metric manifold?

Any references would be appreciated, thanks in advance.

All,

I have wondered about this since I was on high school. So electricity is due to the flow of electrons through the circuit. Is there anything similar but due to a flow of protons or nucleus in a "circuit". Whatever would constitute as circuit in this case.

If yes, is the phenomenon interesting in any sense?

Hey, first post here

As I'm studying about SHM, certain doubts came to my mind

one of the general solution is Acos(wt) + Bsin(wt)
that's ok, I've already achieved this result by using differential equations

but, I still does not understand how the phase enters (while I understand what it does to the equation, I didn't understand if that's arbitrary or anything), and what exactly means the omega, the angular frequency.

thanks for the attention

If we have some initial conditions like initial speed and angle, and we have expressions for the normal and tangential components of acceleration, is it possible to obtain the equations of motion of the particle in the nomal coordinates (x,y)?

I am aware of the fact that we need frequency band rather than a single frequency to send the data over a network, but it's hard for me to visualize why we need behaviour? , like data capacity is completely independent of the actual value of frequency . Gpt gave a trivial answer it's for higher capacity. But how that works, is it like all the frequency overlaps with each other to represent a signal that can do a data transmission ? . I did read fourier analysis where higher the harmonic, better a signal can be represented but for that can't we just take the higher harmonic and skip the rest

EDIT: i guess i confused single signal with single frequency

My original question was : Can we use an instrument to play a constant 500Hz frequency, and vary the intensity (like going from 20dB to 80dB) without a change of frequence ?

When i looked it over, i've came to the conclusion that we can but not with air instrument because of change in air pressure (like when you blow harder in a flute).

Honestly what i found in the internet was a bit confusing and i'd like to have a clear answer about my first question and indirectly does the frequency vary with intensity ?

1. As my book tells heat energy is the total internal energy in the body caused due to potential and kinetic energy of molecules.I can understand the kinetic one but not the potential one, my book tells me that it is due to the attraction of molecules but my question is that how the the attraction between the molecules increases the potential energy?

2)Heat depends on temperature and temperature depends on average kinetic energy of molecules. But temperature tells about the heat of body and heat energy in fact is caused due to potential and kinetic energy of molecules. So shouldn't the Heat depends on average kinetic energy of molecules and temperature depends on heat?

3)Temperature tells about the hotness or coldness of the body then why heat energy is not measured by thermometer I mean to say that by above definition the measurement of temperature should be equal to measurement of heat.

4. why the heat energy always transfer from hot object to cold object?why it can't travel vice versa and pls do not give me analogies I want to what is really happening or is it a fundamental principle which we do not yet know the reason for?

5. when hot object is placed in contact with a cold one how the heat transfers? U will tell me conduction which also my book tells me but I want to know how the heat energy transfers when it is at the end of the hot object and will just enter the cold object I mean that junction how it travels within that junction?

6)why the total amount of heat is equal to the sum of heat of individual body when two bodies are in contact and when it comes to temperature it is the resultant temperature why?

7. I heard that when two bodies in contact reach temperature equilibrium they MAY/MAY NOT have equal heat energy. If yes then why? pls explain this to me.

8. why the definition of 1 calorie of heat is same as specific capacity of heat of body's definition?

Frankly speaking I am a noob when it comes to Heat as it is my first time reading the chapter Heat so if I made any mistakes or conceptual errors pls do not rash out on me but enlighten me.

Title. I’m a history nerd and I’ve been learning more about the Manhattan Project (the creation of the first atomic bomb).

When it comes to splitting atoms I’m curious as to how exactly a neutron is fired at an atom’s nucleus and why neutrons are used specifically to split an atom.

When people talk of the big bang theory it really fries my brain because in order for that to have happened there must've been particles already there in space but how did they get there? Obviously nobody knows or will likely never know but it just confuses the hell out of me.

I also can't comprehend the fact that some people say space is infinite ( probably because as humans we only see things that are finite ) because there has to be something beyond that right?

I never believed in a creator that created everything we know because someone would have to have created the creator and everything truly gets complex.

What are your takes on the theory of space?

I want to plot the displacements from their equilibrium of masses in a 1-dimensional chain with springs. In this problem all masses and spring constants are same.

The equations of motions ends up with a matrix in the following form:

Mu = F

Where F vector includes external forces and it's something like this:

F = [ C, 0, 0, 0, 0 ... 0, 0 ]

U is the displacements.

M is something like this:

[-10.0 -6.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0;

-6.0 -16.0 -6.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0;

0.0 -6.0 -16.0 -6.0 0.0 0.0 0.0 0.0 0.0 0.0;

0.0 0.0 -6.0 -16.0 -6.0 0.0 0.0 0.0 0.0 0.0;

0.0 0.0 0.0 -6.0 -16.0 -6.0 0.0 0.0 0.0 0.0;

0.0 0.0 0.0 0.0 -6.0 -16.0 -6.0 0.0 0.0 0.0;

0.0 0.0 0.0 0.0 0.0 -6.0 -16.0 -6.0 0.0 0.0;

0.0 0.0 0.0 0.0 0.0 0.0 -6.0 -16.0 -6.0 0.0;

0.0 0.0 0.0 0.0 0.0 0.0 0.0 -6.0 -16.0 -6.0;

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -6.0 -10.0 ]

I do this in Python so values are related to that but are in the form of α - k .

I wanted to plot displacements vs. mass indices but my plot looks wrong in terms of that it looks like it's damping. I would expect to something even more random because displacements should not deviate from each other a lot, right? What could be the problem? All did was solving the matrix like M / F.

I know that a star will begin to collapse in on itself when the core starts fusing iron, but when does the collapse really start to occur? Does a star have to have a certain % of it's core as iron?

I was looking at our solar system using this site by NASA https://eyes.nasa.gov/apps/solar-system/#/home

And it seems like all the planets are almost aligned in a 2D plane. Why is that so? My guess is, it has to do something with why planetary rings and accretion disks are also 2D and not spherical.