1. The problem statement, all variables and given/known data I was reading the textbook section on angular momentum, and I'm having some difficulty grasping angular momentum. Here is a question: In the book, it says that the angular momentum L is equal to vector r cross vector p for a particle. But, for a rigid body, the equation is L = Iw. In this case, why isn't the pulley treated as a rigid object. Does this mean that you can take the cross product to find the angular momentum in any case? If someone could please clarify this. Thank you.