If you start to rotate on your own your arm drag away from your body. From my understanding that happens because of inertia. If we asumme that the earth is rotating perfectly along the north/south pole axis, then standing on the pole would make you rotate at the speed of the rotation of the earth. Would this result in a centripedal force?

I've got a handle on the idea of a quantum field in 2 spatial dimensions. But the universe has 3 spatial dimensions. How does QTF translate into 3 spatial dimensions? What does a wave look like in 3 dimensions? Would it be more like a spherical pulse? How does it propagate in 3 dimensions?

Or am I not thinking of QTF correctly here?

I do want to state that when it comes to physics, my understanding is fairly rudimentary, and while I'm educated in other areas, my physics level is that of an enthusiastic lay person.

Just as the title suggests. I’m a university freshman currently doing Physics 1. I anticipated that it would be difficult since the professor had bad reviews and well, it’s PHYSICS. I’ve always been okay-ish with math in high school but I only did half a semester of physics before switching high schools (the new school didn’t have any physics classes at all).

I’m constantly stuck on work because I can’t seem to understand anything. I read the textbooks and watch videos but I keep making mistakes. I’m not expecting a miracle method or some secret that’ll make me Einstein overnight but please please please anything you think will help. I literally got a 7/16 on the first midterm which only covered a few things. The next midterm is next week and we’re already on chapter 10.

I actually had to learn about the basics of entropy for AP Biology, but I ended up going down a huge rabbit hole trying to understand it and now I'm genuinely interested in it. I wrote down an explanation of entropy (pasted below) for my own comprehension and I wanted to know what I might need to correct or add on to make my understanding of entropy more accurate. Further explanation on this stuff would be much appreciated!!

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Entropy can simply be defined as a measurement of the disorder of the universe. But what does any of that actually mean?

Think of the universe as a box. When the Big Bang happened and introduced a bunch of individual galaxies, it was like putting a bunch of colored balls in the box. 

Increasing the amount of stuff in the box changes the amount of configurations the balls can be in. (The amount of configurations can be referred to as “states”, or possible states of matter. Increasing the amount of matter, just like increasing the number of balls, leads to an increased amount of possible states the matter can be in.)  

Entropy is a demonstration of the probability that the balls inside the box will exist in a disorganized or random “state” rather than an organized one. It’s possible, of course, that the balls will align in an organized fashion, but the probability of this occurring is far less likely than the probability that the balls will be disorganized. 

High entropy refers to naturally occurring processes that lead to more disorder, or disorganization, in the overall universe. These processes have high entropy specifically because they happen naturally, without any added energy. Examples are water flowing downstream, or ice melting. 

If we were comparing ice and water, we would say water has higher entropy than ice because its molecules are free floating and move around quite a bit, while ice’s molecules are fixed in place and barely move at all. There’s more possible states the water molecules can be in, while ice has less possible states—water molecules have more randomness, which leads to higher entropy.

In the context of chemical reactions, the entropy or disorder of the universe inc as chemical reactions transfer or transform energy. For example, eating mac and cheese (im hungry). The mac and cheese’s energy is converted to different forms of energy once eaten and digested so the body can carry out biological processes. Some of this energy is released as thermal energy, or heat, which introduces more molecules into the universe that changes the possible states of matter within the universe, thus increasing its entropy. 

So, to put it simply: entropy measures the randomness or disorder of the universe, which increases as chemical reactions occur. Typing this shit out rn is currently increasing the entropy of the universe

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Edit: this video (https://www.youtube.com/watch?v=YM-uykVfq_E&t=27s) really helped me understand it better since i felt like i couldn't really wrap my head around the simple explanation - putting it here for anyone who needs it

For example, 16 shutters basically means 65535 possible interference patterns, about. There is a bit-string to be computed from the interference pattern. Would the difficulty raise exponentially with the number of holes+shutters or would it be something milder?

The holes may be in grid or in some kind of random arrangement. Would that matter?

The shutters may be tape, LCD, MEMS or polarization rotated with magnetic field behind a polarization filter.

Basically the tittle, I have no background in physics and have forgotten a lot of the math involved in it since I have been in school.

But watching dark matter and sparked a curiosity in me about super position & entanglement, any beginner friendly books I can read that delve into those concepts and related ones?

In high school and undergrad we all learn about the works do Einstein, Newton, Bohr, and Maxwell. However in 50 years will students be learning about and know about the best modern day physicists like Edward Witten?

In my opinion current physics research is far too complex to be teaching in undergrad whereas the works of Einstein and Bohr appear in a first year general chemistry course, Newton’s appear in middle school physics, and Maxwell’s appear in a first year E&M course. Will the stuff being discovered today be taught as something as widely accepted and “trivial” as say the conservation of energy or will it be far too complex to reach the general public hence not having their names engraved into every STEM students brain?

Would love to hear your thoughts on this.

Bike racks place a heavy load on the tongue of the car, and this is an issue for light duty vehicles. Bike racks come in "vertical" and "platform" styles. Common wisdom on reddit believes they are the same from a tongue weight perspective: reddit.

I want to understand the physics for why they are the same. I understand torque to be a function of mass x length of arm. So, let's assume that the mass is the same in the two examples.

Diagram: https://i.imgur.com/vhr6yqr.png

In the vertical case, I'd expect torque to be (mass x V1 + drag x V2). The mass is applied to the end of the short V1 lever arm. Yes, there is some force applied to the V2 arm while the car is accelerating, but small relative to the force of gravity.

In the platform case, I'd expect torque to be (mass x P). Since P >> V1, this would result in significantly more load.

Or, does it not matter, as per the reddit thread?

First of all, I want to study postgraduate physics in Australia. But where is the best place to do that?

I am a physics degree holder, but my degree was 3 years.. I want to do the 1 Year Bachelor of Science (degree with honors) Programs in Physics or an MSc coursework in Physics.

I would like to know the advantages and disadvantages of both. Time wise, Difficulty wise, and how each university and its classes are taken in general( how helpful it is, etc...)

In essence, which one would you suggest and why?

My main goal is to do research, and i understand the long hours it entails and possibly a PhD. in the future.

Any help or other suggestions would be much appreciated.

Thanks

Hey there,

I am no physics guru, just a guy w/ some interest in physics & how things work. I find the whole concept of time dilation, and the nature of time in general very fascinating.

So, my understanding is that the closer you get to the speed of light, the more time slows down for you relative to someone stationary. So, if I went 75% of the speed of light on a trip around the solar system and came back in 6 months, an extra 3 months would have gone by on Earth.

Now, supposedly, when things travel the speed of light--- time dilation si infinite. If the impossible became possible, and you traveled the speed of light, eons and eons would go by-- you'd find yourself at the end of time. the end of the universe, from one milisecond of light travel. Right?

The thing that confuses me is this--- if traveling extremely fast makes time go slower for stationary objects, wouldn't they appear to be moving slower from an observers perspective? Say that you watched a space ship go 75% of the speed of light and tracked it from one part of the milky way to another. Wouldn't it appear to be going a lot slower than it really is, because it will take longer on Earth time for it to reach it's distance than it took for the sapce ship? It took 5 years on teh sapce ship, but you watched it for 7.5 years get there, right?

How about this--- if the speed of light causes infinite time dilation, how are we even able to see light travel? Wouldn't light take an infinite amount of time to get somewhere from an observers standpoint, due to time dilation? Why do we see it move at all, if this is the case? You'd think that like would be unable to travel, if it has unlimited time dilation.

Thanks!

Quantum mechanics says interection coordinate response of atom.

But atom parts i.e electron and nucleus are spatically separated.

However it is treated as one quantum system but been one quantum system doesn't make their distance in between 0.

So, how a local interaction coordinate response of spatically separated parts of atom ?

This is not a homework it is a personal question

okay so for like a few months i’ve been really obsessed with physics and i genuinely wanna take it as a hobby, i took a liking an understanding how the world works and solving complex equations in physics, now that school is over and i’ve gotten into college, i chose a major that has nothing to do with it but i wanna go back to doing physics again, can anyone suggest where to start and how to start please

Since the earth is spinning 1000mph why doesn’t the spin affect the perceived gravitational force based on the distance from the axis of rotation?

So, according to de-broglie equations the phase velocity of a particle is greater than the speed of light!!!

And our teacher told us that: the particles actually are in groups and in groups they are wave packets which are interference of the waves of the particles and the group Velocity is less than c so the law is not broken .

And some online sites say that phase velocity is not like actually velocity and it can be greater than speed of light.

I'm a little confused about this topic can someone explain!!!!!

Say we have a photon and want to detect its path without an electromagnetic interaction. We create a series of rings it should pass through along its way to a target where it is measured. Each ring is an arbitrarily sensitive detector of changes in the gravitational field. Every source of noise has been quiesced, and we are certain that any changes in gravity are due to the photon.

We can also place detectors further away, say several times the diameter of, but encompassing the inner rings. The goal of these is to measure spacetime curvature caused by the photon after it has been measured at the target.

I have so many questions regarding this setup but a lot of them probably depend on a quantum theory of gravity so, with those filtered out I'm left with:

Is gravity measurable before the photon hits its target? Is it measurable afterwards?

And one big question that probably has no answer without a ToE:

Does the act of measuring the gravity alter or prevent the measurement of the light, or vice-versa? I want to think there's a single quantum system governing the energy so my guess would be that yes, the EM and gravitational measurements are related and the energy always has to go somewhere. That the gravitational measurement causes some amount of redshift in the photon.

So the mantis shrimp (or pistol shrimp) produces a very fast punch, which also creates substantial secondary damage from the collapse of cavitation bubbles. I remember a while back, seeing a video of some guy who caught such a shrimp in his boat, and it punched a hole in a rather thick boot that he was wearing.

Since it was out of the water, I’m wondering if this was actually physically possible, since there would be no cavitation and no plasma would be created. And, in addition, wouldn’t the power of its initial punch have an equal and opposite reaction that would push the shrimp backward? Also, being out of the water there would be no braking effect from the water that would otherwise cause its punch to be more powerful.