1) in the opposite direction always 2) drag force is the force that acts in the opposite direction of the applied force (air resistance if a drag force for example) 3) frictions forces between the sole and the ground as the owner walks 4) chalk would glide very easily, so a creaking sound could never be produced, but also one could not write anything on the board! 5) I apologize for my lack of familiarity with the kind of sport but the probable answer is to raise the friction of their hands in order to decrease slipping and get a tighter, more firm grip
