While they should have been doing better things with their time, a group of geologists at field camp became highly interested in joints. In particular, they noticed that after hundreds of measurements and many deep, deep conversations, that the joints in their field area mostly clustered around two orientations: the first set was oriented 350/60, the second 210/70. More deep, mystical conversations punctuated by weird junk food cravings led to the determination that these were, in fact, shear fractures. Assuming that these constitute a conjugate set (that is, they formed in response to the same, homogenous stress field), determine the directions of the principal stresses, the angle of internal friction in the rock, and the sense and direction of slip on the joint surfaces. Be cool, use a stereo net.