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1. ### Solving Equilibrium Constant

When I substitute into each other, they all just cancel out to 0=0.
2. ### Solving Equilibrium Constant

The whole question is posted in post number 3. https://www.physicsforums.com/showpost.php?p=4410136&postcount=3
3. ### Solving Equilibrium Constant

I understand how the equations are set up but I can't seem to solve the maths to get the equilibrium constants. Is there something I am missing? Like I said, I am aware that X = 200 thus that value remains at that. Also, From the fourth equation K_{out} = Cl_{out}.
4. ### Solving Equilibrium Constant

From this, finding the concentrations at equilibrium.
5. ### Solving Equilibrium Constant

Homework Statement With the 5 equations, the equilibrium contants can be calculated at the bottom. (See image) My complication I am aware that X = 200 thus that value remains at that. Also, From the fourth equation K_{out} = Cl_{out}. But, I cannot seem to work out the values. If not...
6. ### Integration (ln/e)

Oh yes, that is correct. Silly mistake. Thanks.
7. ### Integration (ln/e)

This is a question... For the following question: y^{'}=\frac{dy}{dx}=3y I get the solution... \int \frac{1}{3y} dy = \int dx \frac{1}{3}ln y = x + c y = e^{3x}+e^{3c} However the textbook example says the solution is... y = ce^{3x} My question is would my answer be incorrect...
8. ### Happy Holidays: Have You Been Naughty or Nice?

Merry Christmas everyone! :smile:
9. ### Maximum Shear Stress

Homework Statement Find the maximum shear stress for \sigma _{xx} = 120 MN/m^2, \sigma _{yy} = 50 MN/m^2, \tau _{xy} = 40 MN/m^2 Homework Equations \sigma _{min} = 0.5(\sigma _{xx}+\sigma _{yy})-0.5((\sigma _{xx}-\sigma _{yy})^2+4\tau _{xy} ^2 )^{0.5} = 31.8 \sigma _{max} = 0.5(\sigma...
10. ### European Experiences of the Icelandic Geyser Ash Clouds

I live in UK. I haven't seen the ash but it's said that it's so high up that it doesn't effect people living here and thus it is not visible. As for people stuck abroad, trains are very booked. Also, in France, there are train strikes which makes the situation harder...
11. ### Solving Distributed Load Homework: Reaction Forces at A and B

Also, what is that dot they have in the bar mean? At point A.
12. ### Solving Distributed Load Homework: Reaction Forces at A and B

Oh yes. It's -(1.8)(0.5). Found 1.8 in the step earlier and forgot to put that in. Thanks.
13. ### Solving Distributed Load Homework: Reaction Forces at A and B

Homework Statement To find the reaction at A and B. (See image below) Homework Equations Moments and Area The Attempt at a Solution Area of load: (0.3)(6) = 1.8kN Moments about A: -(6)(0.15) + RB(0.6) = 0 --> RB = 1.5kN 4. The error and question I get the reaction force at...
14. ### Happy xmas

Just popped by to wish everyone here on PF a merry christmas. :smile:
15. ### Air's Bipolar Junction Transistor Q&A Thread

Hi, I'm learning Bipolar Junction Transistor and need help to confusion which arise so I will keep posting questions which I don't understand to this thread. Thank you in advance. So my questions start: When using hybrid pi model and t model, we determine the dc operating point first. In one...
16. ### Bipolar Junction Transistor

Thank you. Also, if the bottom left resistor branch didn't exist, then the current in the emitter would just be the current in the collector plus the current in the emitter?
17. ### Bipolar Junction Transistor

I've got these two BJT circuits. I want to know if the result are the same. Are both circuits below same? Can the bottom left resistor be grounded and be same as the second circuit. http://img21.imageshack.us/img21/2886/bjtt.jpg [Broken]
18. ### Convolution - Signals and Systems

I will make this my discussion thread. I have many questions to ask which I will post here. Please keep checking. All help will be appreciated. My first question is: For discrete signal, we use variable 'n' and for continuous signal, we use variable 't'. But is the convolution integral valid...
19. ### Questions and Answers regarding Amplifiers

Hello PF Members! I'm revising amplifiers so will post question here occasionally on topics which I don't understand. This isn't homework question as I am asking for my benefit but if you wish for it to be moved, it's fine. :) Here's my first question: I've seen the circuit model for voltage...
20. ### Partial Differentiation [Subscript]

What does the subscript outside a partial differentiation mean? For example: \left(\frac{\partial x}{\partial y}\right)_z What does the z mean above?
21. ### 2nd ODE [Particular Integral]

When finding the particular integral, I understand that for: y''+y'+y=e^{2x}, One would choose y=Ae^{2x} y''+y'+y=x, One would choose y=Ax+B But what am I supposed to choose if I have: y''+y'+y=xe^{2x}?
22. ### Right Hand Rule: Proton or Electron?

For F=Bil, which fingers represent which part? Is it first finger current, middle finger field and thumb is force?
23. ### Right Hand Rule: Proton or Electron?

Homework Statement For this given diagram, determine whether the particle is a proton or an electron. 2. The attempt at a solution Considering at the point where it enters the material. Using RHR, Velocity is downwards (First Finger), Field is outwards (Middle Finger), Thumb points left...
24. ### Electric Potential

But we are considering potential. Do we understand through electric field then use the equation of potential?
25. ### Electric Potential

Homework Statement Particles of the charges q1=+5e (at origin) and q2=-15e are fixed in place with a separation of d=0.24m. With V=0 at infinity, what are the finite (a) positive and (b) negative values of x at which the net electric potential on the x-axis is zero? Homework Equations...
26. ### Gauss Law, Charge, Cavity

So, Am I correct to think that between the Cavity wall and the end of the conducting material, there is no field because charge enclosed is zero hence deriving the electric field through Gauss law would give zero electric field?
27. ### Gauss Law, Charge, Cavity

Is the charge enclosed in the Gaussian Surface zero or q = +3\times10^{-6}C?
28. ### Gauss Law, Charge, Cavity

1. The Question An isolated conductor of arbitrary shape has a net charge of +10\times10^{-6}C. Inside the conductor is a cavity within which is a point charge q = +3\times10^{-6}C. What is the charge on the outer surface of the conductor? 2. The attempt at a solution On cavity wall...
29. ### Forces Of Charge In An Electric Field

Oh yes. So the resolved direction would give that the field is South-East?
30. ### Forces Of Charge In An Electric Field

But there isn't a field which acts on it. :confused: There's only it's electric field.
31. ### Can a physicist be fat?

Yes, some can be fat. But not all may be for the reason stated. However, not every physicist is fat. Most are not. I can say they would eat less as they are more focused on their work thus are not fat. ... There are two sides to a coin.
32. ### Forces Of Charge In An Electric Field

It's a positive charge so field will be radially outwards. Is force also in those direction. If that is the case, then it will cancel out as there will be forces in opposite direction. :confused:
33. ### Forces Of Charge In An Electric Field

Homework Statement A charge of 8\times 10^{-5}C is placed in an electric field (3000\b{i}-600\b{j})N/C. What are the (a) magnitude and (b) direction (relative to the positive direction of the x-axis) of the electrostatic force? Homework Equations F=Eq_0 The Attempt at a Solution...
34. ### Homogeneous Differential Equation

The 'a' test, you can only put 'a' infront of 'x' and 'y' but not in front of the constant? Am I correct? So...dy/dx= \frac{ay+ 1}{ax- 2} And Not...dy/dx= \frac{ay+ a1}{ax- a2} which would lead to 'a' cancelling out.
35. ### Homogeneous Differential Equation

I read that the 'Homogeneous Differential Equation' is one which has form \frac{\mathrm{d}y}{\mathrm{d}x} = f\left(\frac{y}{x}\right) but I came across one example which was \frac{\mathrm{d}y}{\mathrm{d}x} = \frac{x+y}{x+5y} and said that is 'Homogeneous Differential Equation' Too which has 'x'...
36. ### Electric Field/Charge

So you cannot have a shell of uniformly charged density. The electric field inside would be zero for such a case. Is that correct?
37. ### Electric Field/Charge

http://hyperphysics.phy-astr.gsu.edu/HBASE/electric/elesph.html#c2 I realized that there is a for a sphere of uniform charge, the electric field inside is not zero and a conducting sphere has zero electric field inside. Can the sphere of uniform charge also be hollow and solid, just like the...
38. ### Electric Field/Charge

Thanks Doc_Al. Amazing help as always. :smile: __________________ Another question: Isn't the formula for Gauss law (When considering angle), EAcosx, so If the Gaussian surface is perpendicular, there would be no field as cos(90)=0. Why is it that when considering infinite sheet of...
39. ### Electric Field/Charge

I only know the gravitational theory briefly but I understood what you have said. :smile: __________________ Another question: I understand that for a charged conducting sphere, the charge is built up on the surface thus there is no charge enclosed inside (if we are considering Gauss...
40. ### Electric Field/Charge

What is the potential used for? When is it used in context? I know that it's related to Work by W=Ua - Ub.Work is the energy required to move a charge. __________________ Also, for coulombs law, there is a unit vector (r) in the equation. Isn't unit vector value always one? (Thanks for...
41. ### Electric Field/Charge

Hello, I will post questions on this thread on Electric Field/Charge and other topics related to it. I'm studying it and am very weak at it thus any help will be appreciated. For now, here's one question. I've come across two equations for E which are E = (Kq)/(r) and E = (Kq)/(r^2). I...
42. ### MATLAB Ploting Graph - Matlab

How can I plot graph using a few values in the table? I know how to plot if we are to plot a formula but how can I plot pacific values?
43. ### Triple Integral For Moment Of Inertia

Yes, I've taken multivariable calculus. I understand the further process to work out the moment of inertia but the limits and the density function that I have to insert confuses me. Sorry for the confusion. It said y-z plane.
44. ### Triple Integral For Moment Of Inertia

I have general question which need to be answered before I can understand steps which I have to do. There are: When you are told that a solid is bounded by the coordinate plane and the plane x+10y + 2z = 5, are the limits considered to be 0-1 for x-axis, 0-10 for the y-axis and 0-2 for the...
45. ### Calculating Gradient Vector at Point S: x=4, y=8, z=-6

Homework Statement Calculate the gradient vector at the point S for the function, f(x,y,z)=x-\sqrt{z^2 - y^2}; S(x,y,z)=(4, 8, -6). 2. The attempt at a solution \frac{\partial f}{\partial x} = 1 \frac{\partial f}{\partial y} = \frac{y}{\sqrt{z^2-y^2}} \frac{\partial f}{\partial z} =...
46. ### MATLAB Matrix Output (Matlab)

I am making a script-m file to produce results of a formula in a Matrix output. function s = calc(a, b) i = [-a: 1: a]; j = [-b: 1: b]; k = i.^2 + j.*i; A = [i' j' k'] disp('i j k'), disp(A) But, it does not consider all combination. How can I make it stop at a 'i' value so...
47. ### Shortest Distance

I have reached a point of confusion... f(x,y) = x^2+y^2 g(x,y) = x^2+2xy+y^2=150 \mathrm{Equation 1: }2x - \lambda (2x + 2y) = 0 \implies \lambda = \frac{2x}{2x+2y} \mathrm{Equation 2: }2y - \lambda (2x + 2y) = 0 \rightarrow 2y - \left( \frac{2x}{2x+2y}\right) (2x + 2y ) = 0 \rightarrow...
48. ### Shortest Distance

Homework Statement Find the shortest distance from the origin to the curve x^2+2xy+y^2=150. Homework Equations \frac{\partial f}{\partial x}, \frac{\partial f}{\partial y} 3. The problem I'm occurring I'm not sure how to start is thus can't attempt it. I would have used the...
49. ### Understand source transformation

Great, Thanks. Cool. I have a final question regarding this. If the voltage source and the resistor is in series, then it can be changed to current source? If the voltage source and the resistor is in parallel then it cannot be changed to current source? It's ok. You have helped me a lot...
50. ### Understand source transformation

So, if I'm to find the thevenin resistance and have been given both voltage source and current source, is the best method to convert the current source to the voltage source then short circuit the current source? Hmmm... Can you briefly explain what to do if current source and the resistor...