 #1
phantomvommand
 241
 37
 Homework Statement
 See picture below
 Relevant Equations

Dimensional analysis
Solving DE
The top most 2nd order nonlinear DE is the one that has to be solved. Below is the solution. This problem is from Morin's Classical Mechanics.
May I know how he could guess that r = Agt^2?
Firstly, why must g tilda be a variable within r? I do not understand what he meant by 'parameter'.
Secondly, how was it deduced that A must be a constant with no units? Aren't there many constants with units?
Thanks for all your help.