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1. Lagrangian- what potential?

1. Homework Statement There is a joint system of rods and masses.We need to set up Lagrangian. 2. Homework Equations L= T-V , T = Kinetic energy , V = Potential energy 3. The Attempt at a Solution Hey what should we take as the zero of potential. So does the Lagrangian depend...
2. Following first order rxn

OK if we are given the following first order rxn: 2N_2O_5 - > 4NO_2 + O_2 The rate constant is k. Now how would we express the rate law for the decomposition of N_2O_5. - d[N_2O_5]/dt = k[N_2O_5] OR - d[N_2O_5]/dt = 2k[N_2O_5] I think it is the latter but I see all books use...
3. Conductors and fields

How does grounded-ness preserve the argument?
4. Conductors and fields

I had been reading Feynmann lectures , and in it he has shown an argument which proves that E field inside an empty cavity of a conductor is zero.OK. Now he says a similar argument can be used to show that if there is some charge in a cavity of a conductor than the field outside must be zero...
5. Another pH

Actually, there are so many equilibria in this solution I cant figure out what will contribute and the assumption I made(given above) seems to give a wrong answer.
6. Another pH

1. Homework Statement 50ml of 0.10M Na_3PO_4 + 50ml of 0.10M NaH_2PO_4 For H_2CO_3: Ka_1 = 7.5 * 10^{ - 3} Ka_2 = 6.2 * 10^{ - 8} Ka_3 = 1.0 * 10^{ - 12} 2. Homework Equations 3. The Attempt at a Solution Since K_h of Na_3PO_4 > > Ka_2 , I considered only hydrolysis of...
7. Find pH of 0.1 MNaHCO3

1. Homework Statement Find pH of 0.1M NaHCO_3 Ka_1 (H_2CO_3) = 4.3 * 10^{ - 7} , Ka_2 (H_2CO_3) = 5.61 * 10^{ - 11} 2. Homework Equations pH = \frac {1}{2}(14 + pKa_1 + logC) 3. The Attempt at a Solution Now K_h = \frac {Kw}{Ka_1} = 2.3 * 10^{ - 8} > > Ka2 So I neglect dissociation...
8. Modern Physics

Ok then D right? Thnx for replies.
9. Modern Physics

Well what if the experiment is done only once.? If its done many times, answer is probably "d".
10. Modern Physics

1. Homework Statement A single electron with de Broglie wavelength \lambda passes through a slit of width d = 2\lambda. The electron can then strike a flourescent screen. What will be observed on the screen? a) A diffraction pattern b) A single flash has if the electron had moved in a...
11. Center of gravity vs center of mass

Is it different from the center of mass? My book says yes but doesnt answer the question.
12. Thick Double Slit

To notice patterns you need very thin slits, if you have thick slits you wont be able to notice any change since construction destruction all occur so close together.
13. Emfs, work and heat

When we say heat released in a circuit is i^2 RT , who/what is the cause of this energy loss; is it the battery mechanism? Since work done on charge in the circuit by E field is zero, the only other force seems to be the battery mechanism, right? But in text books there is so much implication...
14. Standing wave energy

Well can you tell me what I did is right or not and the thing about PE.
15. Average value of AC over a complete cycle is always zero

Re: Ac Is this the right place to post this?
16. Lots of forces F1,F2,F3

Suppose we have lots of forces F1,F2,F3 etc acting at a point. Then pressure would be the magnitude of vector sum divided by area , limit of area tending to zero or just sum of magnitude of individual forces divided by area, limit of area tending to zero. Also if we are given a surface and...
17. Standing wave energy

1. Homework Statement A standing wave is maintained in a homogenous string of cross-sectional area a and density \rho . It is formed by the superposition of two waves travelling in opposite directions given by the equations y1 = Asin(wt-kx) y2 = 2Asin(wt +kx) Find the total mechanical energy...
18. Average value of AC over a complete cycle is always zero

1. Homework Statement Statement 1: Average value of AC over a complete cycle is always zero. Statement 2: Average value of AC is always defined over half cycle. We need to tell whether these two statements are right, and if 1 is right then whether 2 is its explanation. 2. Homework...
19. Non collinear vectors

Re: Vectors I am sorry but I really mean \alpha + \beta + \gamma = 0 and not \alpha = \beta =\gamma = 0
20. Non collinear vectors

I kinda remember some identity which goes as follows: If a,b,c are coplanar, non collinear vectors then \alpha a + \beta b + \gamma c = 0 => \alpha + \beta + \gamma = 0 or something like this. Can someone help me remember.
21. Incompressible viscous liquid questions

Re: Streamlined That was very nice reply Stovebolt.Thank You. A) Streamlines don't intersect but does that mean they don't interact energetically? B)I think they can speed up or slow down because if we take a crossection of the vessel then the volume of fluid it contains must pass through...
22. Incompressible viscous liquid questions

Which of the following is true in a streamlined flow of incompressible viscous liquid? A) When a fluid is in streamlined flow then there is transport of energy from one layer to another. B) The speed of flow at all points in space is necessarily same. C) The velocity of the liquid in contact...
23. I'm interested in the idea of voltage

Re: electrostatics Sanjoser: I have a seemingly related query here with no proper response https://www.physicsforums.com/showthread.php?p=1977299#post1977299

Why is PV=C
25. Electric current flow in a circuit when a capacitor is fully charged?

Re: Capacitor Well I assumed it was actually the fringe field which caused E field to cancel.
26. Electric current flow in a circuit when a capacitor is fully charged?

Re: Capacitor Thank you very much. Also plz look at this https://www.physicsforums.com/showthread.php?p=1977299#post1977299
27. Non conservative

In an inductor capacitor circuit , what is the kind of E field driving the current? Conservative or non-conservative? And I really dont understand what is the correct way to setup the differential equation for it. This is why: In high school level text books(Resnick Walker), they have applied...
28. Electric current flow in a circuit when a capacitor is fully charged?

Re: Capacitor @hootenanny : But isnt the E field of the capacitor confined only to the region in between the plates. @Pumblechook: Yes but I actually wanted the reason to be in the lines of what hootenanny said. Thnx for replies. Awaiting more.
29. Electric current flow in a circuit when a capacitor is fully charged?

Why doesnt electric current flow in a circuit when a capacitor is fully charged? I mean there is still the battery making the E field, why is it unable to move the electrons of the wire of the circuit?
30. Non electrostatic?

I dont think I am satisfied with the harmonic oscillator analogy because there , there is nothing called field . Awaiting more replies.