1. The problem statement, all variables and given/known data I am first learning about angular motion and came across this formula while doing a homework problem. Can anyone explain to me why ɪa = TR? That is the moment of inertia * angular acceleration = tension in rope * radius. For reference, in the problem it's a stunt guy jumping off a building with rope tied around his waist connected to a cylindrical drum with rope wound around it. I'm only interested in knowing why those two quantities equal each other. Thanks in advance! 2. Relevant equations torque = ɪ torque = TR ɪa = TR 3. The attempt at a solution I already solved the problem, just need clarification.