In community college physics course

>in community college physics course
>prof is talking about light
>says light has energy
>raise my hand
>Tell him that can't be true because light is a mass less particle
>Tell him e = mc^2 demonstrates this fact, as 0xc^2 = 0
>He insists that mass has energy
>i tell him to prove it
>tells me i should just take is word for it because he's the teach
>I walk out of the class pissed off

Just because you're the teacher doesn't mean you're right.

I guess i can't be too supersized, it's a community college after all.

Can anybody give me tips on how i can BTFO him when i get back to his class?

Other urls found in this thread:

en.wikipedia.org/wiki/Energy–momentum_relation
twitter.com/AnonBabble

Dafug "has energy" means?

You're like a little baby

A weak mind such as yourself should listen to my story and take notes

Couple weeks into calculus 1 now, doing well, already past the chain rule and beyond. Quotient rule was a joke. Product rule remains my specialty.

I ask my professor his thoughts on quantum mechanics and partial derivatives. He's impressed i know about the subject. We converse after class for some time, sharing mathematical insights; i can keep up. He tells me of great things ahead like series and laplacians. I tell him i already read about series on wikipedia. He is yet again impressed at my enthusiasm. What a joy it is to have your professor visibly brighten when he learns of your talents.

And now I sit here wondering what it must be like to be a brainlet, unable to engage your professor as an intellectual peer.

All of the deep conversations you people must miss out on because you aren't able to overcome the intellectual IQ barrier that stands in the way of your academic success... it's so sad.

My professor and I know each other on first name basis now, but i call him Dr. out of respect.

And yet here you brainlets sit, probably havent even made eye contact with yours out of fear that they will gauge your brainlet IQ levels.

A true shame, but just know it is because i was born special that i am special. I can't help being a genius, nor can my professor.

Two of a kind is two flocks in a bush.

Sorry lad, he's pretty much right about what he's saying. Sometimes you just have to accept that you're wrong. You don't have to be ashamed.

Don't try to correct him in class, you seem like a dick. Do it after class. You're correct though. But yeah just because you're a teacher doesn't mean your right.

[math]E = \hbar \nu[/math]

He probably didn't expect you guys to know about the energy of a photon and how EM waves carry energy

Prove it.

Can someone make more product rule pasta? It always makes me kek.

Compton scattering and photoelectric effect are probably the easiest example to pinpoint light having an energy per photon.

Think about how the hell lightbulbs are warm if you don't think light carries energy at all. How on Earth plants are able to survive. What do you think the Sun does to provide the Earth with energy?

It's bait but come on people this is simple stuff to say which anyone can comprehend--or in the case of the previous effects, look up empirical data about.

>brainlet in community college
>trying to correct professor
>even when he's wrong

Have you considered suicide?

I did a similar thing OP in my physics course this week and I already regret it
>first time taking physics
>prof talking about velocity and acceleration
>prof says acceleration of a ball thrown into the air is negative at the top of its course
>I'm in wtf mode and wait until the class end to ask for an explanation
>He tries to explain it to my letdown brain and as I'm new to physics I just ask him if acceleration uses relativity concept definition or strict(literal) sense definition in retarded way because we were both out of time. [Because if it is in literal sense, if motion was stopped at the top, it shouldn't have acceleration.]
>He says it is relatively defined that's why it is negative on top
>Feel shitty after that because I already knew what he was said during the class, but I just didn't know anything about how concepts are defined in the study of physics

I was just mad at how physics defined things in a different manner to liberal arts studies so I threw out some tantrums. fuck I'm childish

user, you're being dumb. e=mc^2 is a relationship between mass and energy, ie this mass M holds inside it this energy E, or this energy E, if it were to be converted to mass, would have mass M.

A photon has no mass, but that doesn't mean you just plug it in and say "oh look it has no energy".

A photon has the energy E = Hv. So if you wanted to find the mass with the equivalent energy of a photon, you would say

E = Hv
E = Mc^2
Hv = Mc^2

Solving for M would give you the mass that would contain the same energy has your photon.

solar power

>if motion was stopped at the top, it shouldn't have acceleration
wtf am i reading

Light has relative mass, you fucking idiot.

You are both fucking stupid. You are taking an equation from somwhere and applying it somewhere else and then you wonder why it doesnt make sense. E = mc^2 relates to an object which has 0 momentum. The whole equation is E^2 = (pc)^2 + (mc^2)^2. Voila! everything makes sense once you dont take things out of context and realise physics is a way we describe the world around us and use that to predict how the world is going to behave.
When speak of mass, energy and momentum with regards to a photon we speak of the things dictated by the above equation and everything works.

light bulbs are warm because of the electricity they intake.

plants survive because they use co2 as a fuel source.

If light really did have energy then why do people need to eat food? couldn't we just stay alive from the supposed energy from light itself?

Shouldn't have VELOCITY user.

Also, the liberal arts don't define anything. It's all circlejerking that can essentially be reduced t a plug-and-play template.

>Light is a wave
>Wave has energy
>Light has energy

>co2 as a fuel source

Do they teach you any biology or chemistry?

fucking retard
you are the embodiment of Sci, little know it all, wanna be haz been wanna be.
here is a advice you should always live by "whenever you have a conflit of idea, allways keep in mind that you may be wrong "
the prof probably did not word his claim properly but i hope you realise that you are in the wrong here. light is fundamentally a electromagnetic wave and as such can carry energy E=hf an application would be calculating the energy of the photon release by a nelectron when after excitation.
i really hope you apologize and learn from your mistake .

everyone used to believe the earth was flat.

Your belief than your opinion is correct doesn't mean it's correct.

I can't believe it took this long for this to be posted. Energy is composed of mass and momentum, light has no mass but it does have momentum, p=h/lambda. The E=hv relationship was postulated by Planck to explain the thermodynamic catastrophe of blackbody radiation. Until this point all energy had a squared term.

Acceleration is the rate of change of the velocity. It is constant for a ball thrown in the air, pointing downwards with g=9.8 m/s^2. The velocity of the ball is positive at first, then decreases at a rate of 9.8m/s^2. Eventually the velocity is 0 at the top and continues to fall into the negatives.

>Veeky Forums

>I can't be too supersized
Fucking Americans.

[math]E=mc^2[/math] is only the rest version of the equation, the full version which includes momentum is [math]E^2=p^2c^2+m^2c^4[/math].

>I was just mad at how physics defined things in a different manner to liberal arts studies
How is acceleration defined in Liberal Arts?

>co2 as fuel source
Wewwwwwwwwwwwwwwwwww
wewwwwwwwwwwwww
ewewewewewewe

>American edumacation

p=mv

>non-natural units

I would but we're dealing with someone who probably doesn't know what they are.

Not when it's light

You do realize that a community college physics professor is probably a shitty physicist with a MS degree who couldn't do anything meaningful with their profession.

Be the change you want to see in this world.

Jewels

Haha OP dun spegd.

mc^2 is the REST energy. Light has no rest energy, therefore it cannot be in rest. But that doesn't mean it wouldn't have energy.

Brainlet here. Any books where i can read about this?

Oh yeah well I did intro calc II just for fun

we need a wildememe to prove light doesn't exist

oh yeah him...

>i expected the same quality of education i would get from Cambridge in an $800 community college intro physics course

Wildberger is right about real numbers not being defined though

>Wildberger is right about real numbers not being defined though

They are defined, it is just not satisfactory.

If you have dedekind cuts then you can easily assume that there exists one for [math] \pi [/math], whatever [math] \pi [/math] is. But when you actually try to find that dedekind cut you will most likely use an infinite series that you know converges to pi as your starting point to construct the cut. That will obviously work but that raises the question:

Didn't you already assume the existence of [math] \pi [/math] when you were looking for that infinite series and proved its convergence to [math] \pi [/math]? If so then how come you are now taking that and using it to define [math] \pi [/math]? Shouldn't you define [math] \pi [/math] first and then find such an infinite series?

Weird. Real numbers are weird. But I think we should simply ignore these problems. Maybe in 500 years they will be so deep within analysis that no one will even notice.

>>dedekind cuts
> using poorly defined infinite sets to define an even poorly defined infinite set

>using poorly defined infinite sets to define an even poorly defined infinite set

Hey, that was MY point. Obviously the way we define reals are weird. But we should just forget about the problems with real numbers, you know. Having a perfectly continuous line is too useful. If you ask me, the existence of the real numbers ought to be an axiom.

There are even axiomatic constructions of the real numbers out there. Just use those. As long as we can prove our precious theorems.

Think about what e = mc^2 means. IF a particle has mass, then it has energy. But the implication of that statement is that if a particle has no energy, then it has no mass.

Logically, the statement "If P then Q" implies "if not Q then not P". But it doesn't imply "if not P then not Q."

Your point is true (he likely didn't know what he was talking about), but the answer is this:
E=mc^2 is specifically true for an object with mass m at rest. There is NO reference frame in which light is at rest. So, the only equation you can write down must be the full relativistic energy of a particle with a momentum p, which is E^2 = p^2 c^2 +m^2 c^4 , which is true for all SM particles. Light has no mass in 3+1 dimensions, but does have momentum, so it's energy E=pc.

Not really (in terms of the definition of mass as far as I know it, which is likely more than you know). Free light has 0 mass in typical dimensions (3+1). It has energy because of momentum--not "effective mass," which is only useful in surface analysis.

I'm guessing someone just learned about natural units this year? Cute. Nobody teaching relativistic energy for the first time would use natural units. It's not useful or necessary until much higher levels (after students already understand basic SR completely)

I am honestly confused. What the fuck are you saying ??

Are you seriously defending OP right now......
Just

You don't need to even have a degree to know the physics to tell OP why he's being a fucking idiot

is this bait or is it pasta?

If plants use co2 as fuel, would they be able to survive without any sunlight?

Humans are not capable of photosynthesis, nor would it provide nearly enough energy to sustain us if we could.

both

TL;DRing this thread:
1. OP is wrong
2. Always assume you're the wrong one until you're 100% sure
3. OP is confused

consider the fact that light can produce thermal energy as a result of the phenomenon known as radiation.
light contacts an object (be it an gaseous or solid molecule) and causes it to excite and increase in temperature.

>Think about how the hell lightbulbs are warm if you don't think light carries energy at all.
electrical resistance

You're an idiot, and if I were your professor and had you gotten so frustrated with not being shown the proof, I would have started a lecture on special relativity right there and waited for you to either leave or apologize.

That's not bad. Teachers get that kind of shit all the time. As long as you don't get in a fuss and storm out like OP because your prof wont teach an intro student the intricacies of modern physics.

When exactly did "everyone thing the earth was flat?" Before we invented language? The fucking Greeks could approximately deduce the circumference of the Earth. They were probably also better at geometry than you are right now, even after 2500 years.

>has not studied electrodynamics seriously before
I'm not going to begin to address why your post is meaningless.

By any means how the fuck is no one on this thread not pointing out the socially unnacceptable behavior. i hope there wasnt any cute girls in that class because you just fucked up. lmao and this is at a community college who do you think youre trying to act like a bootleg stephan hawking?

>product remains my specialty
Audible kek

>"If light really did have energy then why do people need to eat food?"
WEEEEEEEEEEEEEEEEEEEEEEEW LAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAD

The problem is that the statement, mathematically speaking as it is written, IS equivalent to saying

IF a particle has energy, Then it has mass

because a = b^2 b^2 = a

and so

IF a particle has no energy, Then it has no mass

is also valid

There is no logical direction in the statement as it is written.

The solution to the paradox isn't to incorrectly claim the direction is implied, but to point out the fact that e = mc^2 is NOT a complete statement.

The full statement contains a term for momentum, which allows for light to carry energy without mass, and is the source for your inferred logical direction regarding the physics.

why don't you jump from a building and live from the kinetic energy for months

>If light really did have energy then why do people need to eat food?

Because evolution doesn't aspire to be boring.

sorry meant to say:

and so
If a particle has no mass, THEN it has no energy
is also valid

E^{2}=p^{2} c^{2} + m^{2} c^{4}.

"ideas of particle physics" by james dodd. it's in between popsci and textbook, audience is meant to be non-physicist scientists. it has a pretty nice discussion of kinematics and why you should use natural units.

en.wikipedia.org/wiki/Energy–momentum_relation

>They were probably also better at geometry than you are right now, even after 2500 years.
we are in 2017

I'm with op on this. you can't tell me for most of my schooling that e = mc^2 then get angry at me when i apply it, the school is completely to blame for this.

the hbar is wrong, should be only h.

"photon has no mass"

It has mass, since it has energy. it can only move with c. which means it bends space time. throught the energy in the changeinge electromagnetic field, it has mass.

Top fucking kek

No. It does not have mass. Mass and energy are not the same thing, and again (as I said above) E=mc^2 is NOT correct...it's only true for the rest frame of a particle. If you know special relativity and EM, you'll know light has no rest frame; it's always moving at c with some momentum p. Then, the full equation is E^2 = m^2 c^4 + p^2 c^2 . I wish people never learned about E=mc^2 (and they often don't teach it alone without the full relation--that's popscience's fault). It's just made annoying pseudo intellectuals sound even more retarded when they pretend to know shit.

It's just a sign convention of sorts.Since you're assuming upward velocity to be positive, the downward gravity is negative. You can use whatever signs are convenient to you while solving the problem.

So someone provided this link which tells you the correct formula, and why E=mc^2 isn't always true. So anybody posting that ignorant shit after this is a retard who's incapable of even spending 10 seconds to click on the answer. So many people on this board pretend they know shit. Sad!

Told to you by people who obviously didn't have any expertise in your field. I hear a lot of people talking about how vaccines are bad, but you are ABSOLUTELY to blame if you buy into it. The point is that there is an infinity of sources for you to easily verify or falsify things, and if you just hear something like E=mc^2 from someone who doesn't know physics, well, if you just blindly believe that, yeah, it's your fault for being a retard.

>there is an infinity of sources

Wrong.


> it's your fault for being a retard.

Define fault.

The point is that there is no shortage of experts on something as simple as special relativity. If you choose to learn from obviously unreliable sources (non-experts), then you set yourself up to "learn" incorrect information. Don't be pedantic--"infinity" of sources is an expression that means that you can look to any expert to find this information; it's not hard to find. The internet today is filled with information. As a rational, intelligent human being, it's your job to weed through what is reliable and what isn't (usually by default to expert consensus). It's your "fault" in the sense that you were willing to accept information from anyone. For example, if some homeless man tells you E = mc^3 and you believe it, you're a retard. Same thing if you just blindly believe your HS teacher given how easily you can find expert opinion. Hell, the fact you're even arguing about stupid shit rather than just shutting the hell up and learning speaks volume about your character, and should give you some insight as to why you know so little.

You aren't retard because you believed it. You are misinformed. That because you didn't demand proof or didn't look it up enough.

This thread is a fucking disgrace

True, but not as much as you to your parents.

>what is relativistic mass?

...

OP read this
Good? Ok, now let me add some further explanation in case you are not tired of looking at a formula with 3 squares.
Light is formed by finite particles named photons. Light is also wave, however, it is easier to explain it as photons. Mostly because waves require further explanation, such as eigenvalues, imaginary units, and many series.
But I diggress. Each photon has quantized energy (E):
E = h·f
Where f is the frequency of the wave [Hz] and h is Planck´s constant.

I am right my dude. i had optics and quantum physics in college.
E=h*v=mc^2
==> m=h*v/c^2
that is the mass of a photon.
you mean it has not mass if it would stand still, which it cannot.(-see special relativity im not your teacher-)

Pls be bait

He literally just told you E=mc^2 is wrong and yet you continue to use it like a fucking retard

Holy fucking brainlet

>light bulbs are warm because of the electricity they intake.
he actually said it the fucking madman
h-hold me Veeky Forums...

David Shaw savage af.

...

You need to go back to re.ddit friend.

E==MC^2 IS ONLY TRUE IN THE REST FRAME OF A PARTICLE

PHOTONS HAVE NO REST FRAME

>light is a mass less particle

"massless particle" sounds like a contradiction to me

I go to med school

It's the normal h though