On the 2012 AP Physics C Mechanics test, I got confused by the sign conventions for torques on question 3. (http://apcentral.collegeboard.com/apc/public/repository/2012_frq_physics_cm.pdf) In the scoring guidelines, (http://apcentral.collegeboard.com/a...12_physics_c_mechanics_scoring_guidelines.pdf), friction was negative so this would be standard reference. Later, the scoring rubric had torque produced by friction positive. However, in standard reference, the torque from friction would be clockwise or negative. Does it matter or is there something I'm missing?