I can see what you're saying about this specific angle in physics.

And actually, others looking at this dynamic, such as J. G. Bennett, or Carol Sanford, also place "goal" and "direction" (which have similar meanings) at 90º in the tetrad:

http://www.systematics.org/sites/default/files/images/tetrad.jpg

That said, I am unclear why you continue to use this precise number when carrying this metaphor into other systems. Wouldn't it be more accurate to say "tangential," or some other term implying that there are two different vectors, but not specifying the exact degree of difference? How can we even quantify the "angle" between nectar gathering and pollination?