Free body diagram of an infinitesimal cross section of cable measuring with infinitesimal angle dθ. TL;DR: the answer is the Capstan Equation. It tells us that, for a given holding tension on one ...

Draw a free body diagram (FBD) of the disk. You will need to temporarily define a coordinate representing the rotation of the disk. For example, you could use the angle θ as the angle of rotation for ...