Recent content by Fabio010

The question is to check where the following complex function is differentiable. w=z \left| z\right| w=\sqrt{x^2+y^2} (x+i y) u = x\sqrt{x^2+y^2} v = y\sqrt{x^2+y^2} Using the Cauchy Riemann equations \frac{\partial }{\partial x}u=\frac{\partial }{\partial y}v...

The question is to check where the following complex function is differentiable. w=z \left| z\right| w=\sqrt{x^2+y^2} (x+i y) u = x\sqrt{x^2+y^2} v = y\sqrt{x^2+y^2} Using the Cauchy Riemann equations \frac{\partial }{\partial x}u=\frac{\partial }{\partial y}v...

Yes, your are right. "Away from the central bulge or outer rim, the typical stellar orbital speed is between 210 and 240 km/s" Instead of 828km/h it is 828000km/h Thanks for the help!

Homework Statement Determine for the nearest star what should be it's recessional velocity if the space between the two stars is expanding according to the Hubble's law. Compare this value with the speed of the sun when it moves with Milk Way. Homework Equations H_{0} = \frac {v}{D}...

Thanks for the help mfb!

Understood! Thanks a lot for the help!

So, the difference is the switching from wavelength to frequency dependence. The results are "mathematically" equal?

So with my result, i can conclude that the dark matter density decreases with the distance from the center of the galaxy. But is not the dark matter suppose to increase with the distance? To maintain the galaxy rotation velocity constant?

anyone?

like this: \vec{} F=\frac{GMm}{R^{2}} a=\frac{v^{2}}{R} The Attempt at a Solution \frac{F}{m}=\frac{GM}{R^{2}} 4\pi \frac{F}{m}=\frac{4\pi GM}{R^{2}} \frac{v^{2}}{R}=\frac{GM}{R^{2}} dM=4\pi\rho (R)R^{2}dR dM=\frac{v^{2}}{G}dR 4\pi\rho (R)R^{2}dR=\frac{v^{2}}{G}dR...

Homework Statement The cosmic microwave background radiation has a blackbody type spectrum. Determine its max frequency and the correspondent wavelenght. Verify if found frequency is a microwave frequency and compare with the following curve: Homework Equations Using the...

Homework Statement Evidence for dark matter comes from “flat” rotation curves of galaxies. Assume that the observed matter moves in circular orbits about the center of the galaxy and that the velocity of the matter as a function of the radius v(r) is a constant. Also assume...

Homework Statement Kundt's Tube.First of all, i used a aluminum rod. Then i rubbed it to cause vibration . Homework Equations a)How can i change the frequency of the sound produced in tube. b)What is the difference of rubbing the metal with more pressure?The Attempt at a Solution a)...

So you are telling me that \vec{E}(A) = \frac{∫-∇.\vec{P}dv}{εo}

Homework Statement A sphere of radius R carries a polarization \vec{P}= k\vec{r}, where k is a constant and \vec{r} is the vector from the center. Find the field inside and outside the sphere. In solution, the field outside sphere is 0. I interpreted that as the field...