Recent content by zachzach

Suppose I have 2 sets of data: day1 and day2. I want to fit a model to both data sets and then compare them to each other to see which one fits the model the best (the fit is done with a computer using non-linear least squares method). The RMS of the fit would be fine except that day1 has much...

\frac{dy}{dx} = \exp \left[ -x - e^{-x} \right] - y^2

That's what I got. Your tuition ended up being right.

The initial velocity is zero? If that was true the projectile would not go anywhere. You wrote: 'A projectile is launched on the Earth with a certain initial velocity'. Also, think about what the velocity is at the maximum height.

Yes, you are missing something. You are only using your intuition and not actual laws of physics. Try to prove your statement mathematically. Use equations of motion when the acceleration is constant (which is very close to being true when the projectile does not go too high).

Your post is not written very well, but I think I may understand you. You can transform wavelength into frequency. My question is, how did you do this? Matter waves and light waves are different. They have different dispersion relations.

Homework Statement Find the pressure as a function of r for the region r<< R where R is the radius of the object. The density goes as \rho = \rho_o {(\frac{r_o}{r})}^2. Homework Equations I know how to get to the answer my problem is dealing with the infinite density at r = 0.The Attempt at a...

Homework Statement Consider a particle moving at close to the speed of light with v \approx c \ \hat{z}. A small oscillatory force F(t) acts on the particle. Consider F(t) to be a first order (eg. linear) perturbation which will not effect v_o, only v_1, the first order component of v...

Homework Statement Consider a semi-infinite, alternating series of thermally emitting planar slabs of two types. Type 1 slabs are at a temperature T_1 with optical depth \tau_1; Type 2 slabs are at a temperature T_2 with optical depth \tau_2. You observe the system at cm wavelengths where...

Yes, I meant to write the equation that you did. So the answer is no then. You can never have a linear combination of non degenerate eigenfunctions that is itself an eigenfunction.

It is easily shown that two eigenfunctions with the same eigenvalues can be combined in a linear combination so that the linear combination is itself an eigenfunction. But what if the two eigenvalues are not the same? Can you still find a linear combination of the two functions that is an...

Why is the dipole moment of two electrons equal to zero? \vec{d} = \sum{q_{i}\vec{r_{i}}} The distance between them is nonzero and they both have charges. It is not obvious to me why this sums to zero.

That makes perfect sense. Thank you very much I have arrived at the correct answer.

Any help? PLEEEASE.

Homework Statement Beginning with \frac{d^2 r}{dt^2} = -G\frac{M_{r}}{r^2} , adding a centripetal acceleration term, and using conservation of angular momentum, show that the collapse of a cloud will stop in a plane perpendicular to its axis of rotation when the radius reaches r_{f} =...