Ive seen several people talk about the theory that our universe is contained within a black hole from a previous parent universe, and I understand the general concept, but there are some questions Ive never heard answered.

1. If we are inside a black hole, shouldnt we see an increasing quantity of mass as the black hole consumes material from the parent universe? If the black hole isnt 'eating', wouldnt it shrink from Hawking radiation -- which violates the concept of universe expansion?

2. Are there theories about the black holes parent universe? If a black hole contained the mass of our universe, how much mass would be in the parent universe? Is the black hole the largest ever concieved, or would it be more proportional to ultramassives like ton 316. How large is the parent universe? Would being inside a black hole alter the fundamental scale of our universe? Are atoms smaller in the black hole than in the parent universe? If not, could we assume the size of the black hole is equivalent to the size of the universe? How big would that make the parent universe?

Kind of alot ik, if there is material on this Id love to read it.

I see physicists talk about invariant or rest mass as a quantity which is intrinsic to a body or system and cannot change. But there is such a thing as mass defect which I calculated in chemistry class. So clearly in nuclear physics at least, mass of a system can change when the constituent massive bodies are combined in certain special ways. As for instance when an atom is created or destroyed. Mass is either gained or lost and you can directly measure this. So mass doesn't seem like an invariant property and can change in motionless bodies. So if this is the case, what exactly is meant by being "invariant"?

Hello I am Just a layperson and do not know much about physics. I would be really thankful if somebody could explain this in simple Terms (If possible).

im a student of physics.

I'm a 12th grade student and the last lesson of physics ive had is back in 9th grade and my brain is completely genuinely fried. Any tips on how to survive and not fail physics? what should i try to study ahead to make it easier for me to absorb the lessons? thank you

If you look at Chladni patterns, it’s really interesting to see how chaos can turn into these very specific patterns.

Do we have a good idea of WHY though?

If our universe was essentially sequential (like a flipbook), and each of those sequences had a duration once time started, it should be possible to have a before "time" as well.

Does that make sense?

Im trying to draw something accurately, and i want to know that, especially if you would be bigger in size, because pf less pressure on your bones/muscles.

You spin faster at the equator right?
Which means the force of the earth spinning is stronger than the pull of gravity at the poles.

Should I move closer to the equator to lose some weight? Or should I try something else?

General relativity says that if you travelled at the speed of light, time stops completely for you. So does that mean that infinite real time has passed?

For my upcoming physics project I've decided to make a stirling engine

I am basing my design on a specific video design .

However, it seems I ran into a problem here. While watching the video, the person making the model used steel wool for the displacement piston but didn't specify which grade.

I asked gemini and it told me to use grade 3 or grade 4 steel wool. I'm a bit skeptical about it. I want to double check this with people who has some experience

Can anyone confirm me which grade would be best for this specific model? Also, this is my first time making this project. I would love to receive some tips and common mistakes to avoid while making this.

Also I am a student and this video is the one which I can make. I saw the rest of them and don't have the materials to make it nor do any shops near me sell those materials

Is Classical Mechanics about determining the future position of a system by studying its motion, or is it about determining the future state of the system. Like for a particle both the goals are equivalent, but when it comes to a system of particles they are not. So what is the ultimate goal of classical mechanics? To determine the state evolution of a physical system or its future motion. The reason for this doubt is that some books claim classical mechanics to be the study of motion bodies acted upon by forces, and some say it is a framework which lays the basis for all of physics, and its job is to figure out the future state of a system.

So after learning a bit of physics beyond my syllabus I learnt that megnetic field creates an electric field. Now using my logic of electrostatics this electric field and basic electomagnetism, the negatively charged particles starts uniform circular motion that is perpendicular to the magnetic field (as the centipetal force that makes the uniform circular motion is perpendicular to the magnetic field). So due to this motion there is a polarisation of charge at the edge (Hall effect I guess) so as there is positive charge on one end and negative charge on the oppsoite end . Electric field in induced perpendicular to the magnetic field. Now if I am right this force is the reason for work done.

So my doubt is what is the magnitude of this force that the the force due to the electric field, I know it is qE but what exactly is the value of E over here?

Also is it due to what I explained over here that we conculde that magnetic field and electric field are perpendicular to each other. Also is my reasoning of circular motion causing the polarisation of charge correct?

Thanks to all of you for clearing this concept!

So I wanna do a research paper on Astrophysics, but my physics is not very advanced? Any advice for beginners??

This man's treadmill has an exercise ball get sucked up under the treadmill when pressed into it from behind. The treads are rotating in the opposite direction the runner is moving, so if the ball slows the treads, the runner should be jolted FORWARD, right? But he is seen tripping/falling backward.

My best guess is that the motor is in a control loop with something that detects the speed of the treads. When the ball is causing friction, the speed of the treads decrease, causing the motor to increase its driving force to achieve a target speed. Then when the ball pops off, the motor stays at the higher driving force and the treads accelerate backward.

That doesn't explain why the motor would have had a harder time reducing power than increasing power. Perhaps when it was increasing driving power to overcome the friction of the ball, the runner was mid-air?

https://www.reddit.com/r/KidsAreFuckingStupid/s/EssXdfhc6C

So we've got this module and on it, it says "an angle of 45° south of east" so Fx is positive and Fy is negative right? So Fx=Fcos(45°) and Fy=Fsin(-45°)? That is what I got based on my research but they are both negative on our modules, it shows Fx=Fcos(-45°) and Fy=Fsin(-45°). Which is right? I dont know why that happens, can someone explain?

I am starting my first year undergraduate in my high school I have done books like I.E irodov and some books from Indian and soviet authors (tho Partially) for mechanics should I go for jhon R taylor?

A stone is tied to a string of length 1.5 m and whirled in a circle at the same constant speed in two different ways.

1. The circle is horizontal, and the string is nearly parallel to the ground.

   1. The circle is vertical. For the vertical circle, the max tension in the string is 15.0% larger than the tension that exists when the circle is horizontal.
      

Draw two free-body diagrams of the stone in the vertical circle (at the point where the tension is maximum) and the horizontal circle

For the horizontal one, I drew a dot, Fg force straight down, and a tension force greater than the Fg force to the left

For the vertical, I drew an Fg force straight down and a Tension force greater than the Fg force up.

Is this correct?

why?

Я хотелтбы сам изучать физику. Начинаю с механики, поэтому хотелось бы порешать задачи на механику.

I'm trying to study scattering amplitudes, and there's a lot that I'm still trying to wrap my head around the math, but one thing that keeps confusing me is what I'm even calculating here. The concept of a scattering amplitude itself kind of eludes me.

See, I understand the state of particle to include information on probability. So, if you have the full knowledge of a particle's state, you also have full knowledge on the probability of finding it at any given position, at any given momentum, etc.. But I also understand the state to evolve deterministically. If you know what the state is at Time A, you can know what the state will be at Time B. Only measurement if probabilistic, that was hammered into me early on.

So when I hear "The chances of system evolving from one state to another", I really feel like I'm missing something. And I've seen scattering amplitudes described that way. So, what is this scattering amplitude that we're calculating?

So I know there are a few things that can happen when a photon comes in contact with a substance.

one of which is thermal absorption.

what i am unclear on for this is what the exact mechanics of that is.

I am sure i am missing something but with scattering, reflecting, photoelectric all seem to be explanations of the conservation of energy other than the thermal absorption portion..

is the kinetic energy due to the electron cloud jumping up an energy level or when it drops back down or is it the retained difference or some other mechanic entirely.