Recent content by covers

Thank you very much, this was exactly what I was looking for! There must be an error in the problem statement then... Sorry for that. Actually I am not sure anymore what I wanted to say with that... but I believe it was something like that: Say (x, y) and (y, z) is in R, then it...

Homework Statement A is some set. R is a relation (set of ordered pairs), and is transitive on A. S = {(x,y) | (x,y) is element of R, (y,x) is not element of R} Show that S is transitive and trichotomic on A. Homework Equations Transitivity: With xRy and yRz ==> xRz The...

Thanks anyway. Maybe it's really an error. I take the opportunity to ask another question about this exercise. At one point, I have to decide whether 'a / (2*m)' is bigger or smaller or equal to 'sqrt(k/m)'. This is relevant when deciding if the oscillator is overdamped, underdamped or...

Thanks for helping! As far as I understand it, the impulse lasts per definition for a certain time interval. In my example here, it goes from t = 0 to t = t0. In my book it is stated as like that: F(t) = m*v0/t0 (for 0 <= t <= t0). The velocity at t = 0 is clearly stated as 0. Maybe it would...

Homework Statement A linear harmonic oscillator is subject to friction(stokes). The Oscillator gets an Impulse at the time t = 0 at the rest position. What is the equation of motion for the time interval 0 - t0?Homework Equations Friction force: Fr = -a * x'(t); a = constant (stokes friction)...

Thanks for the detailed explanation, it did make sense and it did help me! I wish you a happy new year.

Yes, it does make more sense, thanks! But there's still something I don't fully understand. If you cancel out the dz's on both side of the equation, you are left with two integrals, one with respect to v, and the other with respect to z. How do I know that when I integrate one side from v0 to v...

Homework Statement A mass m is thrown vertically from the surface of the Earth with a velocity v0. Find a function that describes the velocity v of the mass m in dependence of its distance z from the center of the earth. Homework Equations m*z'' = -G* m*M / z^2 z'' = dv / dt G =...

I think I finally understood it and I got no question unanswered! Thanks for the time you took to help me, I appreciate it a lot.

I think I got this part! If I'm calculating the centripetal acceleration form the viewpoint of the _E-System, I need to inlcude the r0 vector in my calculations. The part I have marked in the quote, what does that mean? I am also not sure if I am understanding you correctly when you use the...

Therein is the problem. What exactly is the vector r or _r? How can you express the same position vector in two different coordinate systems when their origins to not coincide? I read the link you gave me, and its more or less similar to the theorie within the book I read and where the...

Thanks. Before I think about your advice more carefully, just two short questions: 1-Why should r have a constant magnitude? It depends on the time, doesen't it? 2-When you talk about the position vector r, you talk about it in relation to the _E-system, the system installed on the surface of...

Thanks for the answers! So the coriolis force does not depend on the distance to the axis of rotation. But I do not really undestand it, why does it depend on the distance to the axis on the surface of the earth? What does that mean exactly? I have almost exactly the same problem with the...

I need some help,... On the surface of the Earth a cartesian coordinate system _E will be installed at the latitude ϕ. The axes of the coordinate system are aligned as following: _x1-axis: points up _x2-axis: points north _x3-axis: points east The underscores in front of the variables...

ok, thanks for the explanation. As I read in the documentation of the Hipparcos data, it has astromertic and photomertic data in the catalogue. Do you happen to know what the photometric data is good for then? I know there's a spectral type included in the data also (star class...), is this...