Recent content by guguma

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    Physics I am now a PhD, but feel lost about myself and Science

    Wow, this topic really did get out of hand :), Anyway, Thank You all for your input regarding my future path. I haven't the power alone to change how the entire scientific community progresses, but I will try to stay on top of things and survive at the same time. I disregarded that fact when I...
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    Physics I am now a PhD, but feel lost about myself and Science

    @tech99 Thank You for your kind words, as russ_watters stated, casting a wide net is probably what I should aim for. @ZapperZ Technically since I defended I have a PhD, officially I do not since I did not go through commencement. I found your post very defensive. Agencies requiring the...
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    Physics I am now a PhD, but feel lost about myself and Science

    Hi All, Please bear with me, you can skip to the LSS (Long Story Short) line if you do not want to go through the wall of text. But the complete story carries important information regarding my demise :). After a painful 7 years, I managed to obtain my PhD in Physics. My Thesis and...
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    Calcium Bromide (Anhydrous) Not Dissolving?

    Hi All, So, I am having trouble with a solution I am trying to prepare in the lab which baffles me and here it is: --Water used is DI Millipore Grade Water-- I have Calcium Bromide (Anhydrous) %99.5 from Alfa-Aesar, CaBr(2) is supposed to be highly soluble about 125g/100ml at 0 Degrees...
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    Skiers on Different Sloped Hills?

    They reach the end points at the same time. You can think of it like this: The potential at the problem is the gravitational potential, which leads to a path independent vector field. y=x path would be more comfortable though, one of the skiers on the other paths have a chance to break their...
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    Conditions for Lagrangian Conserved Quantity A(q,p)=qp

    Interesting problem, I tried the poisson brackets got a solution check it out if it makes sense to you. \frac{\partial}{\partial q}A \frac{\partial}{\partial p}H - \frac{\partial}{\partial p}A \frac{\partial}{\partial q}V = 0 p\frac{\partial}{\partial p}H - q \frac{\partial}{\partial q}V = 0...
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    Ehrenfest's Theorem Homework: Solve for d<p>/dt

    On your second step, you cannot carry \psi^* over from the operators and multiply it with \psi What you really need to do is replace \frac{\partial}{\partial t}\psi with the hamiltonian according to the schrodinger equation. You can carry the operators over each other that is correct. But do...
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    Determine Work done on the puck?

    The puck does not stop, you just pull the string thus reducing the radius, The force you apply by pulling the string applies no torque so angular momentum is conserved too. mr1v1 = mr2v2 You now what r2 is Now you can find v2 in terms of v1. So you can find the change in kinetic energy.
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    Determine Work done on the puck?

    Initial KE - Final KE is what you are looking for. The only factor contributing to the energy change is "pulling the string". There is no potential or friction in the problem so the total change in the energy equals Initial KE - Final KE which is the work done "by the puck" stick a negative sign...
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    Why do solutions to the infinite square well potential break down when E<0?

    First of all no need to feel sorry I was not offended. I completely agree with what you are saying. And I never thought differently regarding your last statement about consistent answers. To be honest I am doing a review of QM right now, I never gave much thought about the teeny weeny...
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    Why do solutions to the infinite square well potential break down when E<0?

    I agree on your second post about some imaginary number = some real number argument. But when solving for someother thing you may not be aware of that. For example we may have an imaginary mass for this particular example (not physically correct, but in general you may come across a quantity...
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    Why do solutions to the infinite square well potential break down when E<0?

    Thank you for this lengthy response, I understand all these but through your solution right before we jump to sinh(\kappa a) = 0 We can still go on in this manner sin(ka) = 0 k = i\frac{\sqrt{2m\left|E\right|}}{\hbar} = \frac{n \pi}{a} Then \left|E\right| =...
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    Why do solutions to the infinite square well potential break down when E<0?

    Homework Statement Show that E<0 solutions to the infinite square well potential are not applicable (precisely show that boundary conditions are not satisfied when E<0) Homework Equations Time independent Schrodinger equation V(x) = 0 , 0<x<a V(x) = inf otherwise The Attempt at a Solution...
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    How does the implies connective work in logic?

    The "Implies" connective I have a big problem understanding the logic behind the implies connective. P \Longrightarrow Q The truth table for this is the same as the truth table for Q OR NOT P. The Problem is that I cannot wrap my mind around the fact that the implies statement is...
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    Science Magazine (which one to get)

    I am extremely bored on my way to school. I need something to read on the subway. Reading a book can be troublesome due to transfers and lack of concentration so I decided the best thing would be to read science magazines. The question is, which one? I am a student in physics, I got my...
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