1. The problem statement, all variables and given/known data Why is the tension always tangent to the portion of the cable? The correct situation is on points A and B. Why can't be like on C and D? 2. Relevant equations Newton's force-mass: ##F=ma## 3. The attempt at a solution If i move the portion of the cable and examine, for equilibrium, portion CD, then what about portion AC, does it pull up now, while in position A the portion of the cable on the left of A, if the tension wouldn't be only along the cable, would have pulled down since it was part of the examined cable. So the tension is only along the cable from symmetry only. is it true? i sense it's not the single reasoning.