I'm a high school teacher. I have students competing by racing Lego robots up an incline. I can calculate the force due to friction down the incline and the force of gravity parallel to the plane but am unable to clearly identify the relatioship between these two forces and whether a robot looses traction and begins to spin out. I know that weight distibution is a factor but considering the robot as a point mass, is there a relationship that I'm unaware of. I'd like to be able to predict at what incline a robot will begin to loose traction if the coefficients of friction and the mass of the robot are known.