Recent content by prace

1. 3 Problems involving superposition

Isn't the \lambda for the third harmonic \frac{2L}{3}? If you use hookes law, don't we need to know the spring constant k before using this information to solve this problem?
2. Maxwell's Speed Distribution

Sorry to keep badgering you here, but I do not see how you get \frac{1}{2}C^{-3/2}\int_{0}^{\infty}\sqrt{x} e^{-x}dx The \sqrt{x} should be an x/C no? We let x = Cv², so that makes v² = x/C. The term you are substituting for there is v² not v. That would make the integral...
3. Maxwell's Speed Distribution

Oh ok, so you are saying that the original equation should be: \int 4\pi\ (\frac{M}{2\pi RT})^{3/2} \cdot v^2 \cdot e^{\frac{-Mv^2}{2RT}} dv = 1 instead of: \int 4\pi\ (\frac{M}{2\pi RT})^{3/2} \cdot v^2 \cdot e^{\frac{-Mv^2}{nRT}} dv = 1 ?
4. Maxwell's Speed Distribution

Thanks for the reply, but I still seem to be a little lost. If I let C = \frac{M}{2RT} , that leaves me with 4 \pi \cdot ( \frac{C}{ \pi})^{3/2} \int \frac{x}{C} ... . I don't see how making the C = \frac{M}{2RT} helps me in the latter half of the integral because I have a n term in there...
5. Maxwell's Speed Distribution

Homework Statement Given Maxwell's probability distribution function, P(v) = 4\pi\ (\frac{M}{2\pi RT})^{3/2} \cdot v^2 \cdot e^{\frac{-Mv^2}{nRT}} Where v = velocity, M = molar mass, R = Universal Gas Constant, n = # of mols, T = temperature, solve \int P(v) dv =1 from 0 to...
6. Experimental Proof of Electrical Charge

Hi, I have a question about the transfer of electrical charge from object to another. Basically, my professor stated that if you rub a rod with certain matierials, the rod will become charged. This is due to the convention that Ben Franklin came up with called the triboelectric series. So...
7. Find the Potential as a function of position

Homework Statement A rod of length L carries a charge Q uniformly distributed along its length. The rod lies along the y-axis with one end at the origin. Find the potential as a function of position along the x-axis Homework Equations dV=\vec{E}\cdotp d\vec{l} V=\frac{kq}{r}...
8. Explaination of Curvature

Awesome, thanks guys. You really cleared this up for me!
9. Explaination of Curvature

Homework Statement Find the curvature of y = x³ Homework Equations k(x) = \frac{f"(x)}{[1+(f'(x))²]^{3/2} The Attempt at a Solution k(x) = \frac{6x}{(1+9x^4)^{3/2} I got the answer numerically, but I am looking for an explaination of the graph itself. I chose a relatively...
10. General initial value problem (DE's)

Homework Statement a) Consider the initial value problem \frac{dA}{dt} = kA, A(0) = A_0 as the model for the decay of a radioactive substance. Show that in general the half-life T of the substance is T = -\frac{ln2}{k} b) Show that the solution of the initial-value problem in part a) can...
11. Help with a simple Diff Eqn

Oh cool, even better. Thanks!
12. Ok, so now how do you separate this one?

Yes you did AKG, sorry about that. I just did not see how to factor them. I guess I am not very strong with my factoring and it was not very clear to me. Thanks for the hint Daniel, that will help me out a lot. Ok, going to go and work this out now!
13. DE with an initial condition

I am asked to solve this DE with the initial condition of y(1) = 1. (x+y)^2dx + (2xy + x^2-1)dy = 0 So, after working the problem out, I came to this as an answer: F(x,y)=\frac{1}{3}x^3 + x^2y + xy^2-y My question is what do I do with the initial condition. I assume that I am just...
14. Explanation of this Partial?

\frac{\partial_P}{\partial_y}(2ysinxcosx-y+2y^2e^{(xy^2)} I worked the first part no problem, but the second part I needed a little help from my calculator. This is what I got: 2sinxcosx-1+4ye^{(xy^2)} My question is, why does the partial of 2y^2e^{(xy^2)} come out to 4ye^{(xy^2)}...
15. Ok, so now how do you separate this one?

ok, so I tried it and I got 1+\frac{5(x-y+1)}{xy-2x+4y-8} which does not seem to help me out too much. The form of both the numerator and the denominator do look a little suspicious. Is there a way to factor them like we can for a problem in the form ax^2 + bx + c?