1. The problem statement, all variables and given/known data A bob of mass m attached to an inextensible string of length l is suspended from a vertical support. The bob rotates in a horizontal circle with an angular speed ω rad/s about the vertical. About the point of suspension : (1) angular momentum changes in direction but not in magnitude. (2) angular momentum changes both in direction and magnitude. (3) angular momentum is conserved. (4) angular momentum changes in magnitude but not in direction 2. Relevant equations torque = rXf angular momentum = rXp 3. The attempt at a solution i know that answer is a and how it came but i feel it is answer c,because there is only one force tension, and the torque produced by it is zero about point of suspension as r is parallel to f,so shouldn't momentum be conserved?