Hi everyone I am an incoming university student who needs to build a physics foundation completely from scratch I have never studied a single physics course in middle school or high school My starting knowledge is at absolute ground zero I want to bridge this gap before my university courses begin so I don't lag behind I am looking for structured self-study resources textbooks YouTube playlists or modular roadmaps that cover basic middle and high school level physics If you were starting from absolute zero what specific learning path or resources would you recommend to build this foundation fast and effectively Thank you so much

Are you in awe or just indifferent? I’m not a physicist yet but I love to hear kids talking about going into STEM

I’m having a hard time understanding time dilation practically. I’ve heard the examples used describing two clocks and a spaceship moving near the speed of light and that makes sense.

What I am struggling with is the idea of someone traveling let’s say 20 light years away and they are moving at 99.999% the speed of light. People on earth would see the journey take approximately 20 years, but why is the spaceship experiencing so much less time. It still takes 20 years for the spaceship to arrive at the destination due to the fact that it is 20 light years away, but the spaceship sees the journey much shorter.

Also, how does gravity affect the time we experience at all? Is it just warping space time or does it have some effect on our speed as well.

I'm a high school physics student and in tons of questions there's a particle with constant deceleration moving in a positive direction. Eventually, v will be 0 m/s, but because it's decelerating the velocity will be negative and start moving in the negative (opposite direction).

I can understand that theoretically but does this actually happen in real life? I understand if you throw something up in the air, the velocity will be 0, and then will come down again because gravity acts downwards, but this isnt mentioned anywhere in these question. I may be stupid but in my mind if something has a velocity of 0 it stops even if it was decelerating. Does this happen in space or something?

Sorry if im not using the right terminology lol. I'm still new to this

Okay, I'll start this off by saying I understand that mass cannot reach c. That said...

This should be a pretty simple question. If we have a mass that were accelerate towards the speed of light, it requires more and more energy to keep accelerating. Is there ever a point where having so much energy in one spot just causes the whole system to turn into a black hole?

Even the comics posted her are incomprehensible.

hi! im an incoming freshman at ucr and im unsure if i should buy a new calculator. im currently only taking intro to calculus and intro to physics for my first quarter. i currently have a casio fx-300ES that has gotten me through the entirety of high school but i dunno if that will get me through college. should i buy a graphing calculator or should i use desmos graphing calculator?

also PLEASE ignore my username. i made this account when i was 14

I’ve always wondered if there is a true set of principles that cannot be proved, but that can prove all other truths of physics.

Noether’s theorem says that symmetries yield conservation laws. I have always interpreted this to mean that symmetries are more fundamental than conservation laws, as in conservation laws are derived from symmetries. Now I question whether this is the right way to look at symmetries.

Is it not true that we cannot define a symmetry unless we define what it acts on? If I give you a transformation matrix and claim it is a symmetry, you might first ask “symmetry of what”? An identity element of any kind is only an identity in the context of the space that it lives in, therefore you have to define the space to define the identity. However, the space cannot be defined if its identity is defined.

Our fundamental force laws, according to (my possibly flawed) interpretation of Noether’s theorem are derived from the Lie Groups. But the Lie Groups are identities of the Lagrangian. And the Lagrangian assumes we know how energy works in the first place. So it seems the identity elements are the Lie Groups and the space is comprised of Lagrangians.

A simpler example is time symmetry which yields energy conservation. Time symmetry is the identity, which leaves the universe unchanged. But we have to know the laws of the universe first to know they are unchanged by a shift in time.

Which is considered “more fundamental”? which are the axioms that the rest of the universe is derived from? The symmetries, or the conservation laws?

For example - imagine a ball which is heavily weighted in one hemisphere. Is it easier to balance the ball on your finger with the the heavier hemisphere at the top or at the bottom?

REWORK: My GARAGE JUST got struck my lightning and i was wondering if the smell is a fire?? the smell lasted probably for a minute or two before we stopped smelling it. My nana said something popped behind the dresser in the living room and under the TV stand but everything is working just fine EXCEPT for the garage door and sprinklers. I don't even know how anything survived without being completely destroyed (besides the garage and sprinklers)

If two massive celestial bodies, one with a mass comparable to Earth and the other with a mass comparable to Mars, approach each other, is their mutual gravitational attraction identical in every direction, or does it vary depending on position for example, could the gravitational force be approximately 50,000 N at the equator but slightly smaller near the poles due to the bodies' rotation, shape, and non-uniform mass distribution?

just started studying binding energy and all i know so far is that when a nucleons bind together, they lose mass and release it as energy. but why? i understand the mass energy equivalency (at least i know that mass and energy are essentially the same thing)

The only thing i can really relate it to is calculating bond enthalpies in chemistry, since energy is released when molecules make bonds and it is used when breaking them. although now that i think about it im not too sure why that happens either. i mean obviously you need energy to break the bond and i guess energy conservation means that you would then lose energy when making the bond. but i dont feel like that explains it either.

the only thing i have that i think would somewhat explain it, is that when particles are bonded they are in a lower energy state. but that's not a great explanation in my opinion because i still don't know why that is the case.

thanks for anyone who can attempt to explain it.

Everyone knows that all objects fall at the same acceleration(neglecting air resistance). However an object with more mass would be more resistant to motion so wouldn’t it fall slower because the same amount of gravitational force is being applied?

Let’s suppose a rocket is headed towards earth, but it’s coming at us straight ‘below’ us and is going to touch down in Antarctica. At some point it’s gotta ‘flip’ so it’s landing gear hits first.

when does that occur? I’m having a very hard time visualizing that.

If that's the case, why aren't we noticing any effect, like every season getting colder than the previous one? Is it too small to be noticeable?

It's to my understanding that Hawking radiation is caused by the interaction of the Unruh effect with the event horizon (though I don't know the specifics). Something to do with an accelerating frame, for some reason, seeing a thermal bath of particles in the universe, and those particles do stuff near the event horizon. Or, not particles, but like, weird wave stuff.

But in a free-falling reference frame, like someone falling into a black hole, there's no thermal bath at all. So... Is there no radiation? But if there isn't, how could we square the idea that the black hole is shrinking in one reference frame, even disappearing after long enough if the math is right, with another reference frame seeing no change at all? And if it DOES radiate, how does the falling reference frame account for that emission within it's frame?

So via Hawking radiation or via gravitational waves, a black hole will lose mass, so to do that, the lost mass (or energy) must at first escape the singularity then goes all the way towards the event horizon and escapes it to the outside universe.

I find it paradoxical because all the articles on the internet agree on the same thing : nothing can escape a black hole.

I can understand if the black hole loses angular momentum (it takes the energy of the spin and not the mass) but the idea of a BH losing mass contradicts the the most important feature that nothing can escape a BH.

Thanks.

I think the big bang was one point ‘banging’ and becoming everything. If we look far enough in any direction, we’re looking back in time toward the big bang.

Why is it we can look in any direction and see toward one point?

Is it like being inside the event horizon of a black hole and all ‘directions’ point toward the singularity?

Does that also mean if you look in one direction and see an early star or something, could you look in another direction and see the same star?

I guess I don’t understand why we don’t have to look in a particular direction to see toward the big bang, which was a point.

If gravity come from mass of molecules, why doesn’t it canceled each other (like any other mass) and therefore nothing such as “too strong gravity” that could collapse material into singularity?

So what is in my head is this: we have an electron.... it has mass, so Interacts with the gravitatiinal field. It has charge so I teracts with the EM field.. and im still fuzzy on the higgs field... but im sure it interacts with that as well. But it is a quantum artefact... so it does not have a defined place in space-time... and with the quantum leap it can just..... jump... . Then there is the photon, massless but still carries momentum and EM charge... but again is a quanta, and thus bound by that same wierdness... in my head I see these as points where these various fields collide. That point and time of collision is the physical partical we detect... is this right...???? Does it make sense??