# Search results

1. ### Help with Integrals (one of which involves erfc).

I'm using Green's Functions for heat conduction problems, and I'm trying to solve the following integral: Homework Statement http://img28.imageshack.us/img28/4923/026307b169b04faa8364086.png [Broken] Where: http://img820.imageshack.us/img820/3742/6332938c445f4b9e8da8ba5.png [Broken]...
2. ### Laplace Equation Solved by Method of Separation of Variables

Homework Statement Homework Equations Assume the solution has a form of: The Attempt at a Solution It looks like a sine Fourier series except for the 2c5 term outside of the series, so I'm not sure how to go about solving for the coefficients c5 and c10. Any idea?
3. ### Statically Indeterminate Beam

I have a fixed-end fixed-end beam with two roller supports as well and a load applied in the center of the beam, as shown below. I've chosen my redundant forces to be the force at B (point up), the force at C (pointing up), the force at D (pointing up) and the moment at D...
4. ### Statically Indeterminate Beam to the Sixth Degree

As the title says, I have a statically indeterminate beam to the sixth degree and I'm attempting to use the superposition method (aka force method) to solve for the reactions. My additional equations will be the angle at points A, B, C, and D as well as the deflection at points B and C. Is...
5. ### Potential at a point due to two charges

I've been working on this problem and I cannot find out where I am making a mistake. Homework Statement Two charges, each with a value of +q, are placed a distance d apart on the x-axis. Find the potential at a point P a distance z above the x-axis on the z-axis The Attempt at a Solution The...
6. ### Calculating Displacment from acceleration

I have some accelerometer data from an object and I want to find the natural frequency and displacement of this object. A plot of the recorded data looks like this: As you can see, I did a FFT of the signal to find it's components, and at ~20Hz, we can see the main component. I know...
7. ### BSME to MSNE

A little background information. I am currently working a summer internship out at Lawrence Livermore National Laboratory and will be going into my senior year for my B.S. in Mechanical Engineering at San Jose State (in very good academic standing). Recently I have become interested in going...
8. ### Simple Calculus Problem

I'm trying to determine the centroid of the shape below: The curve line is that of a circle, but the equation of for a circle, (x-a)2+(y-b)2=r2, won't work here for obvious reasons, but the equation y=r-\sqrt{2rx-x^{2}} does. To determine the location of the centroid, the formula is: To...
9. ### Photon's frame of refernce

Sorry if this has been asked, but I did a search and didn't find a relating topic. This thought came to me a few days ago when a friend asked me about time dilation. Time beats slower and distance is shorter for a moving reference frame with respect to a non-moving reference frame, and the...
10. ### Relativistic momentum and ke quesion

Homework Statement A Lambda0 (L0) hyperon at rest decays into a neutron and what? (a) Find the total kinetic energy of the decay products. (b) What fraction of the total kinetic energy is carried off by each particle? I have both the decay process and the total kinetic energy. L0 -> n+ p°...
11. ### DiffyQ question

Homework Statement In an experiment, the isotope I-128 is created by bombarding I-127 with neutrons. This creates 1.5E6 I-128 atoms per second. Initially there are no I-128. The half-life of I-128 is 25 minutes. Find the equation that represents the number of I-128 atoms as a function of time...
12. ### Quantum Harmonic Oscillator

Can someone explain to me how they went from U(x)=(1/2)kx^2 to E=(n+1/2)(h/2pi)w? http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/hosc.html
13. ### Nuclear resonance

Homework Statement The greater the width of the nuclear resonance,.... a) the greater the rest energy of the resonance b) the greater the lifetime of the resonance c) the lower the rest energy of the resonance d) the shorter the lifetime of the resonance e) nothing Homework Equations...
14. ### Issue finding out what meson this is.

I have a down quark paired with an anti-charm quark (dc) and I can't find what particle this makes. I checked the PDG's site, but got lost in their list of mesons (they didn't see to get the quark combination, or if they did, they did a good job at hiding it).
15. ### Question about intrinsic angular momentum

Homework Statement If electrons did not have intrinsic angular momentum, the states occupied by the electrons int he ground state of He would be a) (n=1, l=0) and (n=1, l=0) b) (n=1, l=0) and (n=1, l=1) c) (n=1, l=0) and (n=2, l=0) d) (n=2, l=0) and (n=2, l=1) e) (n=2, l=0) and (n=2...
16. ### Wave functions

Ok, so the wave function for an electron that is confined to x>=0nm is: w(x)=0 for x<0nm w(X)=be^(-x/6.4nm) for x>=0nm what is the probability of finding the electron in a 0.010nm-wide region at x=1.0nm? I have no clue how to even start on this. This is no coverd in my physics book...
17. ### Inductance and coils

Homework Statement Coil 1 has L=25mH and N=100 turns. Coil 2 has L=40mH and N=200. The coils are rigidly positioned with respect to each other, and their mutual inductance is 3.0mH. A 6.0mA current in coil 1 is changing at 4.0 A/s. (a)What magnetic flux Phi12 links coil 1 to coil 2, and what...
18. ### LR circuit energy dissipation

Homework Statement A LR circuit has a 10V battery, 5.50H inductor, and a 6.7 Ohm resistor. The battery is closed at t=0. (a) What is the time constant of the circuit? (b) How much energy is delivered by the battery during the first 2 seconds? (c) How much of this energy is stored in the...