1. The problem statement, all variables and given/known data This is from a homework that's already been graded, and this is the solution: http://desmond.imageshack.us/Himg842/scaled.php?server=842&filename=angler.jpg&res=medium [Broken] I just want to know the reasoning behind the placement of the the 30 degree angles in the free body diagram given only the original picture. 3. The attempt at a solution The only reasoning that I can see is that if you readjusted the axis to it's more typical x and y directions, then the force resulting from gravity acting on the object would overlap the -x axis. So by tilting the coordinate axis 30 degrees, a 30 degree angle forms between the G force and the NB force, because the G force always points directly down. Is there a better proof for this? Am I wrong in my reasoning for the placement of that angle? If it is relevant, this is for a statics class.