Recent content by Romeo

Pervect- very kind, thank you. It's annoying that MTW is the only text i couldn't get my hands on (on-loan), so have a plethora of others (although Weinberg and Schultz have been useful). Zanket- Who authors that text? (I'm going to feel very silly if that's the MTW title... ) Best Romeo

Consider a model in which we let a body fall (radially) into a star, being the simplest example of the schwarzschild solution, in which the angular parts of the solution may be ignored, so that we consider: ds^2 = -(1- GM/r) dt^2 + (1- GM/r)^{-1}dr^2. I have been told that this may be...

Thanks Arildno. I was a little concerned about double (incidentely, it was a triple...) posting, but did so only because I thought patrons of the mathematics section may have a better insight- which seemed the case, since you very quickly responded :). I'll keep it in mind for the future...

Thank you pervect, it's an approach I hadn't considered. Regards Romeo

Thank you all, apologies for the double post, all is accounted for in the Diff Equ forum. And again, thank you Arildno for the solution. Regards Romeo

Much appreciated Arildno and apologies if this is a little late coming. I hope my double posting was not too imposing- it would have been unnecessary had the original post in the College Homework forum taken a helpful direction. Regards Romeo

Thank you anyway Whozum. I think maybe I should have stated that there will of course not be constant acceleration, hence your approach is invalid. However, there is now a solution in Diff Equ/ns, so check out what I was trying to do! Regards Romeo

1-dimensional problem in Newtonian gravity- HELP! The problem is this: Given sun of mass M and a body of mass m (M>>m) a distance r from the sun, find the time for the body to 'fall' into the sun (initially ignoring the radius of the sun). Our first equation is therefore \frac...

The converse would be: If we have a right-angled triangle, then it's sides satisfy n^2 +1, n^2 -1, 2n . So you find a single particular example where this fails, and succeed in showing that the converse is not true. Hope that helps, good luck. Ro-me-o

The problem is this: Given sun of mass M and a body of mass m (M>>m) a distance r from the sun, find the time for the body to 'fall' into the sun (initially ignoring the radius of the sun). Our first equation is therefore \frac {d^2r}{dt^2} = \ddot{r} = \frac {GM}{r^2} . I am able to...

BobG, I understand what you're intending to say, but haven't quite got what I'm trying to say: I have the second order differential equation \ddot{r} = -GM /r^2 to solve, aiming to find an expression for 'r', which will then simply be be used to find an expression for the time it takes for...

Appreciated Woozum, but you mis-read my post. Maybe i should clarify further: \dot{r} = \frac {dr}{dt}, and that i solved the first integral of this second order differential equation, but cannot, in particular, solve this: \int \frac {1}{\sqrt{1/r - 1/R}} dr = -\sqrt{2GM}\int dt...

The problem is this: Given sun of mass M and a body of mass m (M>>m) a distance r from the sun, find the time for the body to 'fall' into the sun (initially ignoring the radius of the sun). Our first equation is therefore \ddot{r} = \frac {GM}{r^2} . I am able to integrate this...