Search found 79 matches

by Clever-Username
Tue Jul 19, 2011 8:13 pm UTC
Forum: Mathematics
Topic: Chaos pendulum
Replies: 19
Views: 4274

Re: Chaos pendulum

I have a strong feeling the OP is trying to get us to complete an assignment/presentation for him.... We don't do your homework for you here...
by Clever-Username
Mon May 30, 2011 7:39 pm UTC
Forum: Science
Topic: Combustion catalyzed fusion
Replies: 14
Views: 2229

Re: Combustion catalyzed fusion

The energy that would be required to produce a magnetic field of that magnitude to create pressure high enough to create fusion would exceed the energy output of your fusion reaction by A LOT.

In other words, maybe it's possible, but it's not at all efficient.
by Clever-Username
Thu May 26, 2011 4:00 pm UTC
Forum: Science
Topic: Could time be measured in meters?
Replies: 83
Views: 11717

Re: Could time be measured in meters?

There are books out there on general relativity (and other topics mind you) that use a different naming and notation convention than in typical introductory textbooks on physics. I have a very hard time believing that any physics textbook would treat distance and time in the same units using any co...
by Clever-Username
Thu May 26, 2011 1:57 pm UTC
Forum: Science
Topic: Could time be measured in meters?
Replies: 83
Views: 11717

Re: Could time be measured in meters?

That conversion only makes sense if you're referring to the speed of light and the distance it travels in 'x' seconds (or minutes, hours, days, years, etc.). There are books out there on general relativity (and other topics mind you) that use a different naming and notation convention than in typica...
by Clever-Username
Tue May 24, 2011 5:35 pm UTC
Forum: Mathematics
Topic: Need help with Gaussian Elimination
Replies: 8
Views: 1285

Re: Need help with Gaussian Elimination

At your stage in the course there really isn't much use to LU and LDV factorization. However, if you continue on in linear algebra you'll find that they get really helpful at time in identifying symmetric matrices, finding the quadratic form of an equation, and as already mentioned operation countin...
by Clever-Username
Mon May 09, 2011 5:06 pm UTC
Forum: Science
Topic: Quantum Entanglement
Replies: 39
Views: 6540

Re: Quantum Entanglement

... In the MWI, on the other hand, there's no faster-than-light communication. The electron doesn't change state when we measure it, it was *always* spin up (or spin down). However, there was a very closely related world with the opposite orientation that caused interference, preventing us from mea...
by Clever-Username
Wed May 04, 2011 6:05 pm UTC
Forum: Science
Topic: Quantum Entanglement
Replies: 39
Views: 6540

Re: Quantum Entanglement

Yeah, the idea that the electrons have a specific spin before we open the box is called a hidden-variable theory and is entirely wrong . Not really what I was referring to with my posts. I was trying to get him to realize the subtle mechanics behind entanglement. I guess I failed with my descriptio...
by Clever-Username
Wed May 04, 2011 3:06 pm UTC
Forum: Science
Topic: Quantum Entanglement
Replies: 39
Views: 6540

Re: Quantum Entanglement

It's still a 50/50 statistical thing, either the particle is in one state or the other. We have no way of knowing until we observe it. What I'm trying to say is that the electrons are already in one of those states, but until we observe the particle and 'collapse' it's wave function we have no way o...
by Clever-Username
Wed May 04, 2011 2:56 pm UTC
Forum: Science
Topic: Quantum Entanglement
Replies: 39
Views: 6540

Re: Quantum Entanglement

The electrons are entangled whether someone is looking at them or not. Even without observation one will be spin up, the other will be spin down but there is no way of us knowing which is which until we observe them. Opening the box collapses what WE see to either spin up or spin down, but the elect...
by Clever-Username
Mon May 02, 2011 4:41 pm UTC
Forum: Science
Topic: Quantum Spin?
Replies: 16
Views: 2454

Re: Quantum Spin?

There's a reason most professors begin teaching Introduction to Quantum Mechanics by telling you not to think about the electron as a particle, but to think of it as a wave. When you think of it as a physical particle, a billiard ball per se, you get into these visualization issues when trying to cr...
by Clever-Username
Fri Apr 22, 2011 10:30 pm UTC
Forum: Science
Topic: God Particle?
Replies: 12
Views: 2248

Re: God Particle?

That would be the Higgs boson. It's a rare form of matter, and it is thought to possibly be related to dark matter, which is something astrophysicists made up to explain why their models of the universe don't work correctly. Astrophysicists came up with the idea of Dark Matter and Dark Energy in or...
by Clever-Username
Sat Apr 02, 2011 7:28 pm UTC
Forum: Science
Topic: Physics for a Mathematician...
Replies: 2
Views: 870

Re: naturall Philoſophie for a spelling...

Stupid word filters, so you're a mathematics major wanting to study theoretical physics Best I can suggest to get into it a little is Roger Penrose' The Road to Reality. He begins with a very mathematical standpoint on hypersurfaces and hyperfunctions and segways into general relativity. He covers p...
by Clever-Username
Sun Mar 27, 2011 1:24 am UTC
Forum: Mathematics
Topic: Ever felt "off your game" mathematically?
Replies: 15
Views: 2633

Re: Ever felt "off your game" mathematically?

The more advanced stuff I learn the less confident I get with BASIC mathematics... If the topic is something I'm currently studying I usually feel pretty good about it... but if it's high school stuff I fail miserably... While talking to the rental agent at an apartment I'm looking at I asked how ma...
by Clever-Username
Fri Mar 04, 2011 5:00 pm UTC
Forum: Science
Topic: Laser Tractor Beam soon? ZOMG!
Replies: 5
Views: 1298

Laser Tractor Beam soon? ZOMG!

http://blogs.discovermagazine.com/80beats/2011/03/03/how-to-build-a-laser-tractor-beam-in-theory/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+80beats+%2880beats%29 So cool. Though it's still just a simple theory I think it's remarkable that there is even a theoretical possibil...
by Clever-Username
Thu Jan 27, 2011 5:19 am UTC
Forum: Science
Topic: easy physics problem.....
Replies: 3
Views: 2372

Re: easy physics problem.....

Create a mock-free body diagram for the velocities. One vector east with the appropriate wind speed. Another vector north for the final velocity north. Now what is the required velocity vector required to cancel out the eastern wind and result in the pilot travelling north
by Clever-Username
Sat Jan 15, 2011 10:10 pm UTC
Forum: Science
Topic: I just found the velocity of.. something..
Replies: 7
Views: 1449

Re: I just found the velocity of.. something..

Looks like the tangential component of velocity.

edit - and btw there's no need to change vdt to dx:

[math]P_{avg} = \frac{1}{\Delta{t}}\int{Fvdt} = \frac{1}{\Delta{t}}Fv\Delta{t}[/math]
[math]\frac{P_{avg}}{F} = v[/math]
by Clever-Username
Tue Jan 11, 2011 12:23 am UTC
Forum: Science
Topic: Undergraduate physics in a book?
Replies: 7
Views: 2036

Re: Undergraduate physics in a book?

Haven't personally read Penrose's book, but the reviews I just read seem to say it's a difficult one to read for someone with no significant physics/math backround... in other words: good luck. I should also recommend The Feynman Lectures on Physics, I personally love them and they're a great refere...
by Clever-Username
Sun Jan 09, 2011 11:46 pm UTC
Forum: Mathematics
Topic: Math Problem Help (flying fish trajectory)
Replies: 6
Views: 1870

Re: Math Problem Help (flying fish trajectory)

Graphed it using matlab... looks pretty good to me, why do you feel like it's the wrong answer?? :?

graph.jpg
by Clever-Username
Sat Jan 08, 2011 9:49 pm UTC
Forum: Mathematics
Topic: Taylor series remainder in integral form
Replies: 1
Views: 1352

Re: Taylor series remainder in integral form

Guh, I tried working it all out with your formula for the remainder term and it didn't work. The reason? There's an error in your remainder formula, the real form is: R_{n}(x) = \frac{1}{n!}\int_{a}^{x}(x-t)^{n}f^{(n+1)}(t)dt It works with that formula, look at the wi...
by Clever-Username
Fri Jan 07, 2011 11:10 pm UTC
Forum: Science
Topic: Aluminum foil in a microwave - when should you be worried?
Replies: 24
Views: 14142

Re: Aluminum foil in a microwave - when should you be worrie

Sparks in a microwave are never a good thing and people are in the right state of mind to run over and turn it off. WHY is it never a good thing? It seems like you are just repeating what someone else told you without having any practical knowledge of the subject at all. Are you kidding me? How can...
by Clever-Username
Fri Jan 07, 2011 5:09 pm UTC
Forum: Science
Topic: Aluminum foil in a microwave - when should you be worried?
Replies: 24
Views: 14142

Re: Aluminum foil in a microwave - when should you be worrie

Sparks in a microwave are never a good thing and people are in the right state of mind to run over and turn it off. WHY is it never a good thing? It seems like you are just repeating what someone else told you without having any practical knowledge of the subject at all. Are you kidding me? How can...
by Clever-Username
Thu Jan 06, 2011 11:09 pm UTC
Forum: Science
Topic: Aluminum foil in a microwave - when should you be worried?
Replies: 24
Views: 14142

Re: Aluminum foil in a microwave - when should you be worrie

Do you have an oven? Easy solution to heat it up = throw it in your oven. This avoids the issue with your microwave. Sparks in a microwave are never a good thing and people are in the right state of mind to run over and turn it off. However I could go on a huge shpleel about what's already said but ...
by Clever-Username
Wed Jan 05, 2011 11:02 pm UTC
Forum: Science
Topic: scientific field
Replies: 22
Views: 3155

Re: scientific field

I'll warn you right now that what you have a 'passion' for in high school may not be where you end up throughout university and further. I was a die-hard Chemistry lover in high school. I loathed going to biology and physics but i did it anyway because of the credits required to get into university....
by Clever-Username
Fri Dec 17, 2010 4:40 am UTC
Forum: Science
Topic: Privatized Space Travel
Replies: 148
Views: 11606

Re: Privatized Space Travel

To mars and back? That's going to be a little longer than a 'couple hours', try nearly a year to get there, same on the return trip.
by Clever-Username
Wed Dec 08, 2010 4:56 am UTC
Forum: Science
Topic: Can someone explain the joke?
Replies: 16
Views: 3056

Re: Can someone explain the joke?

I think the joke is just that in Physics, everyone tries to make their equations more elegant and simple, by using modified notation and super/subscripts to represent longer equations. And from what I understand, there is an inherent understanding that 'the more elegant the solution, the more likely...
by Clever-Username
Wed Nov 24, 2010 2:24 am UTC
Forum: Mathematics
Topic: [DONE, Thank you!] Laplace Transform contradiction??
Replies: 9
Views: 1198

Re: [HWK help] Laplace Transform contradiction??

I observe that it'd work out nicely if you had 32s^2 rather than just 32s in the first term you produced for the second method. Perhaps you might want to look closely at your work surrounding that term to see if you may have lost a factor of s? Yep... I screwed up taking the second derivative... Ou...
by Clever-Username
Wed Nov 24, 2010 2:18 am UTC
Forum: Mathematics
Topic: [DONE, Thank you!] Laplace Transform contradiction??
Replies: 9
Views: 1198

Re: [HWK help] Laplace Transform contradiction??

How? Expanding out
[math]F(s) = \frac{32s}{(s^2 + 16)^3} - \frac{8}{(s^2 + 16)^2}[/math]
doesn't give me
[math]F(s) = \frac{24s^2 - 128}{(s^2 + 16)^3}[/math]
when I expand it out I get:

[math]\frac{-8s^2 + 32s - 128}{(s^2 + 16)^3}[/math]
by Clever-Username
Wed Nov 24, 2010 2:10 am UTC
Forum: Mathematics
Topic: [DONE, Thank you!] Laplace Transform contradiction??
Replies: 9
Views: 1198

Re: [HWK help] Laplace Transform contradiction??

How so? Doesn't (-t)^2sin(4t) imply the 2nd derivative of the laplace transform of sin(4t)? That's what I have in my notes :S edit - well if you want to be 100% correct F^{(2)}(s) = Laplace of (-t)^2 f(t) Where f(t) = sin(4t), thus the second derivative of F(s) = lapl...
by Clever-Username
Wed Nov 24, 2010 1:43 am UTC
Forum: Mathematics
Topic: [DONE, Thank you!] Laplace Transform contradiction??
Replies: 9
Views: 1198

Re: [HWK help] Laplace Transform contradiction??

=( 46 views and not a single suggestion? I put a lot of work into making the latex notation all nice.
by Clever-Username
Wed Nov 24, 2010 1:39 am UTC
Forum: Science
Topic: Thanksgiving take-home physics quiz...
Replies: 15
Views: 1970

Re: Thanksgiving take-home physics quiz...

Not really what I meant: if we have t = k W^2/3, then by dimensional analysis we have [k] = [t]/[W^2/3], in SI we get [k] = \frac{s}{\frac{kg^{2/3}m^{2/3}}{s^{4/3}}} or [k] = \frac{s^{7/3}}{kg^{2/3}m^{2/3}} so k = 0.66 \frac{s^{7/3}}{kg^{2/3}m^{2/3}} But... you know, that only works for a 3 dimensio...
by Clever-Username
Wed Nov 24, 2010 12:28 am UTC
Forum: Science
Topic: Thanksgiving take-home physics quiz...
Replies: 15
Views: 1970

Re: Thanksgiving take-home physics quiz...

Perhaps assume 0.66 is a constant with units that makes it compute?
by Clever-Username
Tue Nov 23, 2010 7:21 pm UTC
Forum: Mathematics
Topic: [DONE, Thank you!] Laplace Transform contradiction??
Replies: 9
Views: 1198

[DONE, Thank you!] Laplace Transform contradiction??

As part of a homework assignment we were given the following problem: Find the laplace transform (how do I do the L symbol???) of t^2sin(4t) using first principles, then confirm your answer using the differentiation rule Using sin(4t) = \frac{e^{i4t}-e^{-i4t}}{2i} Plugging into the d...
by Clever-Username
Mon Nov 15, 2010 8:58 pm UTC
Forum: Fictional Science
Topic: Clarke's Third Law and Harry Potter.
Replies: 21
Views: 6674

Re: Clarke's Third Law and Harry Potter.

You could get some sulfer-hexafluoride and either a) make your voice awesome, or b) make stuff levitate
by Clever-Username
Fri Nov 12, 2010 3:58 am UTC
Forum: Science
Topic: [HOMEWORK] Electromagnetic induction problem (spinning loop)
Replies: 1
Views: 626

Re: [HOMEWORK] Electromagnetic induction problem (spinning l

Thinking about it some more, if I define the following: current loop.jpg and take the following integral: \int_0^L{\omega B r d\vec{l}} = \omega B r \int_0^L{d\vec{l}} = \omega B r L This will give me half the area, but I am only taking into account the upper half of the loop, thus I multiply my res...
by Clever-Username
Fri Nov 12, 2010 3:30 am UTC
Forum: Science
Topic: [HOMEWORK] Electromagnetic induction problem (spinning loop)
Replies: 1
Views: 626

[HOMEWORK] Electromagnetic induction problem (spinning loop)

So i've been scratching my head with this problem for a while now and was hoping someone could either say yay my solution is correct or to point me in the right direction: Supposed the loop in [the picture below] is rotated around the y axis. What is the maximum emf when \omega = 35.0rad/s, B = 0.45...
by Clever-Username
Sat Nov 06, 2010 5:12 pm UTC
Forum: Science
Topic: Guy on facebook page denies germ theory
Replies: 39
Views: 5976

Re: Guy on facebook page denies germ theory

Huh... you think an ethics board would have some issues with deliberately infecting people. Well then...
by Clever-Username
Sat Nov 06, 2010 5:41 am UTC
Forum: Science
Topic: Guy on facebook page denies germ theory
Replies: 39
Views: 5976

Re: Guy on facebook page denies germ theory

If it weren't for ethics boards we could prove this easily. Identify a culture of said germs, keep a group of people in sterile isolation for several months, as to set them as a control. Split into 2 (or several) groups. Introduce 1 group to the 'germs', keep the other group neutral. Who develops th...
by Clever-Username
Thu Nov 04, 2010 3:21 am UTC
Forum: Science
Topic: Chemistry Safety
Replies: 24
Views: 2422

Re: Chemistry Safety

gotta make sure they dont touch the liquid though of course. When I was a kid they had an open day at the university. LN is one of those weird substances which is both dangerous but also surprisingly hard to injure yourself with. They did all the tricks,poured some out on the ground and me and the ...
by Clever-Username
Tue Nov 02, 2010 2:46 am UTC
Forum: Science
Topic: Chemistry Safety
Replies: 24
Views: 2422

Re: Chemistry Safety

Sodium Thiocyanate has a pretty vicious MSDS sheet: (This is for a 98-100% concentration of the stuff, check what % your mixture is, the less it is the less harmful it will be) http://www.jtbaker.com/msds/englishhtml/s5210.htm Inhalation: May cause irritation to the respiratory tract. Symptoms may i...
by Clever-Username
Tue Nov 02, 2010 2:10 am UTC
Forum: Science
Topic: AP Physics problem-- pulleys (of the frictionless variety)
Replies: 16
Views: 3523

Re: AP Physics problem-- pulleys (of the frictionless variet

Ok then, instead of being rude maybe we should actually help this guy. Look at each pully and draw the free body diagram for it, look at the mass hanging, what are the forces acting on it? How do they balance? To get you started I drew the FBD's for you: I hope the picture makes sense, I haven't rea...

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