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    Testing Missed the reg deadline for the physics GRE

    I'm in the same boat. My decision to graduate this year came after the deadline for the physics GRE. I'm still applying to 7 grad schools, though: University of Minnesota, Brown University, UW-Milwaukee, CUNY, Stony Brook, Brandeis, and University of Pittsburgh. None of them require the physics...
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    Summer 2013 Math and Science REU Thread

    Yeah, I haven't anything at all myself, excepting two rejections. I'm starting to think it'd be a good idea to make back-up plans for the summer just in case.
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    Summer 2013 Math and Science REU Thread

    Yeah, I just got rejected from Notre Dame. 300 applicants for 12 spots. Hahaha.......
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    Increase in Wavelength of an LED Immersed in Liquid Nitrogen

    Hi, I've been working on an experiment where I dip LEDs into liquid nitrogen and note the color change. All online sources I've seen predict that the wavelength of the light emitted by the LED will decrease upon immersion. What I've been observing, however, is a sudden decrease in...
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    Does anyone else feel like it's all been studied already?

    I see now that I didn't formulate the thread title very well. I don't at all feel that it's all been "done." I'm aware of plenty of open questions out there, and I'm sure they will keep coming. My feeling is mainly that I have nothing to contribute to the open questions, which is probably just...
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    Does anyone else feel like it's all been studied already?

    You make a good point! The likely discovery of the Higgs Boson is very exciting. You're also right that I just don't know enough to be getting into the real deep questions. I would be more excited if I was able to understand the actual theory behind the Higgs Boson, which I probably won't be...
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    Does anyone else feel like it's all been studied already?

    Thanks everyone for the advice. This is very helpful (and encouraging). I guess I just needed to hear from some people who have actual experience with research. It sounds like I definitely shouldn't expect so much from myself ;D Don't want to neglect this either haha
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    Does anyone else feel like it's all been studied already?

    Hello all, I'm currently an undergrad student studying math and physics. It's my hope one day to go to grad school and pursue some sort of research within physics. Recently, though, I've been having a sort of crisis (haha): Evidently I'm completely void of novel research ideas. Every...
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    Difficult Improper Integral Involving Arctan(x)

    Interesting! I think I see how to prove the generalization.
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    Difficult Improper Integral Involving Arctan(x)

    Awesome! Thank you both. Those were just the thoughts I needed to do it myself. Sorry for not posting my initial attempts...they both involved rewriting the integral as an iterated integral and switching the order (I figured out two ways of doing this). The trouble was that each time the...
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    Difficult Improper Integral Involving Arctan(x)

    So recently I've been working through some challenge problems from my old calculus textbook for fun. I'm stuck on one of the integrals, though, and can't find any solutions online. This isn't for's for my interest and hopefully the interest of others. Here it is (sorry about the...
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    Eugene Wigner's take on math's role in natural science

    That's a really thought-provoking question. Different people have different answers, and there seems to be no general consensus. A partial explanation is that we actually develop mathematics ourselves in order to describe the natural world. In other words, it works because we make it work. But...
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    Linear Differential Equation Help

    The equation becomes exact if you multiply both sides by the integrating factor μ = y2. You can then find the solution using regular methods for solving exact equations. Not sure if Wikipedia explains the method very well, but...
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    Partial integration of the function f = 1

    I think that makes sense. Thanks!
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    Partial integration of the function f = 1

    Given a function z(x,y), is the following expression valid: ∫(1)∂z = z Does this even make sense? I came up with this in my differential equations class, but I'm not sure if it actually means anything.
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    What is momentum?

    You could also think of it as "the quantity of motion" of an object.
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    Spherical Coordinate Systems(Cartesian, i think it called)

    Do you mean the gravitational force or the acceleration due to gravity? I think the coordinate system is arbitrary, so you could define gravitational acceleration to be positive or negative depending on how you set up your coordinate system. If you mean the constant g, though, then that...
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    Favorite physics videos on internet

    For the German speakers out there, Professor Harold Lesch's series Alpha Centauri is great for astrophysics. There are a ton of 15 minute podcasts from 1999-2007 Another series (also in...
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    Push mass up a ramp

    In other words, as long as the force and dispacement vectors are perpendicular, it doesn't matter what their components are.
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    Push mass up a ramp

    It might help to think about the situation in terms of a coordinate system and the dot product. You could define your coordinate system in any way, and it wouldn't matter. Work is defined as a dot product of force and displacement: work = F*d*cos(theta), where theta is the angle between the...
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    When we r considering a ball that is thrown at 45 angle, with the air

    The air exerts a sort of friction force on the ball, taking away some of its mechanical energy and converting it into thermal energy. So as the ball travels along its trajectory, some of its kinetic energy is being converted into thermal energy. Hence the ball's velocity is decreasing, which...
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    Momentum and Impulse

    The wall does gain momentum. But really you need to consider the wall and the earth together because the wall is attached to the earth. This single component of the system has an enormous mass, so its change in velocity is imperceptible. You can imagine, however, that if a wall is not...