I tried your suggestion u = r/r_max:
dr = r_max*du
Integral[ r_max*du/sqrt( 1/u*r_max - 1/r_max ) ]
With a bit of algebra:
r_max^1.5 * Integral [ du / sqrt( 1/u - 1 ) ]
I fed that integral into Mathematic 6's Integrate function as:
Integrate[ (1/u - 1)^-0.5, u]
What I got...
Ehild,
Thanks for the welcome and for your help. Very much appreciated!
I've been lurking here off and on for years, I just tend to read and listen a lot more than I write -- for some strange reason. :-)
J.
Homework Statement
A comet is released from rest at a distance r_max from the sun.
Therefore it has no angular momentum.
We can assume the sun is a point mass ( i.e. sun's radius is zero ).
How long does it take for the comet to hit the sun?
Let m = comet mass
let M_s = sun's mass...