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  1. ?

    Understanding Entropy better

    Do you mean this relationship? dS = \frac{\delta Q}{T} \Delta S = \int \frac{\delta Q_{reversible}}{T} If yes, then this would be a good starting points I guess: http://en.wikipedia.org/wiki/Clausius_theorem And then the explanation under the "definition" section here...
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    Moments and Bending Moments

    Oh ok, fair enough. Yeah. I was looking at beams with point loads but it was too difficult to come up with an expression that described the bending moment (because it was described piecewise with discontinuity in shear forces) so I gave up. I think I see the problem with my expressions...
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    Moments and Bending Moments

    Hello, I have a small question about moments and bending moments. So, if I have a beam with a loading given by q (N/m) which is given as a function of x then what do these calculations get me? \int xq(x) dx \int (\int q(x) dx) dx The first integral gives me the moment about a point because I...
  4. ?

    Beam Deflection

    Ok, never mind. I tried solving the M=EI \frac{d^2y}{dx^2} equation for the scenario 1 on the link, using boundary conditions y(0)=0 and y'(0)=0 and I got the given result so I guess it is how they got all the results. I used the result I got on my second post and it gave the right answer. The...
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    Beam Deflection

    So, I have found some equations for deflection of beams that I'm assuming come from solving the above differential equation for basic scenarios: http://www.advancepipeliner.com/Resources/Others/Beams/Beam_Deflection_Formulae.pdf So, my question now is, can the principle of superposition be...
  6. ?

    Beam Deflection

    Homework Statement Homework Equations For small deflections: M=EI \frac{d^2y}{dx^2} The Attempt at a Solution To solve a problem like this, I think I was told I need to study the deflection and displacement of the beam. If I said that the deflection at points x=0 and x=3L have to be 0...
  7. ?

    Problem on distribution of charges between charged/uncharged spheres

    I think the charge is going to equalise. So you can just add the charge of A and C and divide it by 2 to get the total charge on each one. So, lets say A has 0 and B and C have Q. A touches B so they both have Q/2. A touches C. The charge distributes equally. So, total charge is 3Q/2. So, there...
  8. ?

    Amplifiers homework problem

    Homework Statement Homework Equations dI = \frac{\partial I}{\partial V_{GS}} dV_{GS} + \frac{\partial I}{\partial V_{DS}}dV_{DS} The Attempt at a Solution I was just wondering why \small V_{G} is at 0. I have solved the entire question (there are more parts :P), but I could only do it...
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    Electric Potential Difference involving Alpha Decay question

    I was thinking maybe use the F = E q = Vq/d = ma ? But that means any non zero potential will be able to bring it to rest (lower potential will simply take long to do it and the nucleus will travel a larger distance while decelerating).
  10. ?

    Complex Impedance

    Thanks man. I looked at your question but I don't know how to do it. I was thinking maybe use the F = E q = Vq/d = ma ? But that means any non zero potential will be able to bring it to rest (lower potential will simply take long to do it and the nucleus will travel a larger distance while...
  11. ?

    Electromotive force in constant flux

    How will you get a function for phi in terms of t so you can differentiate? Look at this link: http://en.wikipedia.org/wiki/Faraday's_law_of_induction#Faraday.27s_law_as_two_different_phenomena It talks about circuit moving and field changing as 2 different phenomena and I think it will be...
  12. ?

    Complex Impedance

    I found another thread that went through some of the derivation: https://www.physicsforums.com/showthread.php?t=267367 They talk about phasor representations and so on, which is a little beyond my mathematical knowledge so I think I'll just have to learn the relationship you gave me. How would...
  13. ?

    Complex Impedance

    I think you are right. How did you derive the Z = R + j(XL - XC) I think you are using the final general solution (sort of the solution you get after you plough through all the maths). I think you get Z = R + jXL for inductor and Z = R - jXC for a capacitor. But am not too sure. I wanted to...
  14. ?

    Electromotive force in constant flux

    Yo dawg, consider each side of the rectangular loop. The top horizontal side "cuts" no flux cause it ain't got no balls. The right side cuts flux so there IS an EMF cause it's one badass playa. The left side cuts flux too and there IS an EMF generated but it's like ya know consider the direction...
  15. ?

    Electromotive force in constant flux

    Flux is being "cut" use -v cross B for each infinitely small unit length dl The velocity goes with r d(theta)/dt
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    Complex Impedance

    Homework Statement Question 2 on this paper: http://www.eng.cam.ac.uk/teaching/past_papers/examples_student/examples_IA/P3_LCD_Q/1ap3lcdq003 Homework Equations Z = V/I V=L di/dt The Attempt at a Solution for part a of the question: I began with V = Vo cos(wt) And I = Io cos (wt + k) I...
  17. ?

    Quantum Mechanics pendulum problem

    The equation I gave was wrong, sorry man. I have a new relation: 9 - 2Lx + x^2 = 0 which gives x = L +- sqrt(4L^2 - 36) / 2 This comes from considering it's equilibrium and max and getting an isosceles triangle. You split it into 2 right angle triangles. Use pythagoras to get 3^2 + (L-x)^2...
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    Quantum Mechanics pendulum problem

    Again, just a shot in the dark, but by height I'm guessing you mean the height the mass reaches at it's full swing? You know its 3 cm far, and l long. The height is x= 3 /(tan ( 90 - arctan(3/l))
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    Quantum Mechanics pendulum problem

    If you have the period, don't you have the length? T = 2pi sqrt(l/g) approximately. From this you can get the height? I have no knowledge of quantum mechanics so this is just a shot in the dark.
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    Satellite motion and Moment of Momentum

    http://img194.imageshack.us/img194/4638/001ofa.jpg [Broken] Can the image not be seen? I've scanned the question and posted it there... I got rid of it and now there's a link.
  21. ?

    Satellite motion and Moment of Momentum

    Homework Statement http://img194.imageshack.us/img194/4638/001ofa.jpg [Broken] Homework Equations Not too sure to be honest. The Attempt at a Solution Well, r1 cross product m v1 = r2 cross m v2 But, there is a force applied so I have to take that into account. I was thinking, The moment...
  22. ?

    Gauss' Law and it's meaning

    Thanks bro. So I guess I was right after all. I don't have a professor or colleagues to go to when I can't solve a problem so you will be seeing a lot of me in the future.
  23. ?

    Gauss' Law and it's meaning

    Hello all. I have been trying to learn some Physics in my spare time and I came across Gauss' Law. I've been thinking about different cases and conditions and I have been confused by the actual meaning of Electric flux being 0. Homework Statement If I consider a sheet of uniform charge per...
  24. ?

    Quick! Help! Axe?

    The deodrant...I mean. I cough when I smell it. But I got it for X-Mas from my mum, so I am using it :(
  25. ?

    Quick! Help! Axe?

    :yuck: Thats the one I am using now....:eek: It smells worse than Denim Black....too strong...wayyyy tooooooo strongg. But beauty lies in the eyes of beholder....
  26. ?

    Quick! Help! Axe?

    OK, just go to the market and bring this home:
  27. ?

    I am SICK of being the friend

    Been throught this and wore 16 different t-shirts....
  28. ?

    Quick! Help! Axe?

    The Axe Effext is really the axe effect! Why don't you try Axe Voodoo. It is the best :!!)
  29. ?

    Diamond ring for v-day

    No wonder thou art Mr. Popular :shy:
  30. ?

    Diamond ring for v-day

    Ooooooo............. double post, youre liable to be banned!! :devil:
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