- #1
Stargate
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Can three people here post one hard physics problem for me to solve??!
(That's one person per problem)
(That's one person per problem)
Challenge Accepted: 3 Hard Physics Problems for You to Solve!
- Thread starter Stargate
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Homework Help Overview
The discussion revolves around a request for challenging physics problems suitable for various educational levels, particularly focusing on advanced topics such as Yang-Mills equations, Navier-Stokes equations, and QED, as well as more accessible high school-level problems involving projectile motion and satellite orbits.
Discussion Character
- Mixed
Approaches and Questions Raised
- Participants propose a variety of physics problems, ranging from advanced theoretical concepts to K-12 level questions. Some express concern about the appropriateness of the complexity of the problems for the intended audience.
Discussion Status
The discussion is ongoing, with participants actively suggesting problems and clarifying the level of difficulty. There is a mix of advanced and simpler problems being offered, and some participants are questioning the feasibility of solving certain problems given the assumed knowledge level.
Contextual Notes
There is a noted tension between the advanced nature of some problems and the K-12 context of the forum, with participants highlighting the need for problems that are solvable within the constraints of high school physics knowledge.
- #2
arildno
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1) Give a rigourous derivation of the Yang-Mills equations
2) Prove, that under smooth initial conditions, the Navier-Stokes equations will not blow up in finite time.
3) Determine the range of initial conditions three bodies solely attacted by mutual gravity can have in order to exhibit periodic motion.
Good luck!
2) Prove, that under smooth initial conditions, the Navier-Stokes equations will not blow up in finite time.
3) Determine the range of initial conditions three bodies solely attacted by mutual gravity can have in order to exhibit periodic motion.
Good luck!
- #3
dextercioby
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That's not fair,Arildno,you took all three of them... 
Here are my three:
1.Derive the effective action of QED in the first order of perturbation theory (i had this problem at the QFT exam,last year).
2.Derive the Poisseuille-Hagen formula (1839) starting from the Navier-Stokes equations.
3.Prove that Abraham-Lorentz equations are violating the principle of causality.
Daniel.
Here are my three:
1.Derive the effective action of QED in the first order of perturbation theory (i had this problem at the QFT exam,last year).
2.Derive the Poisseuille-Hagen formula (1839) starting from the Navier-Stokes equations.
3.Prove that Abraham-Lorentz equations are violating the principle of causality.
Daniel.
- #4
rachmaninoff
He only wanted one problem per person, arildno.
- #5
arildno
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Well, but I gave him CHOICES, didn't I?rachmaninoff said:
He can pick the easiest one if he likes.
- #6
Stargate
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arildno and dextercioby, pick one problem that you want me to solve.
- #7
arildno
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A bit more serious, I'll pick Daniel's 2.
(It's at least doable, and not too difficult)
(It's at least doable, and not too difficult)
- #8
dextercioby
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Stargate said:
The first in the most interesting.Pick the first.Pay attention with your calculation,though.
Daniel.
- #9
Stargate
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I need one more problem from a different person and I'll get back to you by next monday. Ok?
- #10
rachmaninoff
You guys,this is a K-12 forum! You can't assume graduate level knowledge here.
Here's my one, HS-level problem:
1) A 53.0kg spherical projectile, 27.0cm in radius, is fired at an angle 38.5 degrees to the horizontal at 12,350 m/s. Find the maximum height by Euler's method approximation (h = 0.0005) without using electronic aids (you'll need a bit of paper for this). Keep in mind the gravitational force will not be constant. Include air resistance.
Here's my one, HS-level problem:
1) A 53.0kg spherical projectile, 27.0cm in radius, is fired at an angle 38.5 degrees to the horizontal at 12,350 m/s. Find the maximum height by Euler's method approximation (h = 0.0005) without using electronic aids (you'll need a bit of paper for this). Keep in mind the gravitational force will not be constant. Include air resistance.
- #11
dextercioby
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Hey,man,this is K-12.Air resistance is usually proportional with velocity,somtimes even with its square.Nonhomogenous gravity field+air resistance:that's a horrible diff.eq.he'll be getting.Without air-resistance,maybe he'll have a chance.
Daniel.
Daniel.
- #12
Stargate
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I'm a 9th grader by the way so I would like 9th grade problems please.
- #13
rachmaninoff
I apologize, this whole thread is being quite inconsiderate, myself included.
A solvable problem: What is the altitude of a satellite in geostationary orbit, given that there are 86,400 seconds in a day, and [tex]r_{earth{[/tex] = 6,370km? (fun problem, really)
A solvable problem: What is the altitude of a satellite in geostationary orbit, given that there are 86,400 seconds in a day, and [tex]r_{earth{[/tex] = 6,370km? (fun problem, really)
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- #14
rachmaninoff
Dextercioby: Actually I sidestepped the D.E. part when I asked him to use Euler's method.
- #15
dextercioby
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A very short and interesting problem:
Compute the atmosphere's mass.Assume all constants are given (u may use tables of constants and calculators for the numbers).
Daniel.
Compute the atmosphere's mass.Assume all constants are given (u may use tables of constants and calculators for the numbers).
Daniel.
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