1. The problem statement, all variables and given/known data 1. For the ground-state of the 2D rigid rotor what is the expectation value of the angular momentum? And what is the corresponding uncertainty in this value? 2. Describe in words what the uncertainty in position is. 3. Explain why the rigid rotor can have vanishing zero-point energy and still be consistent with the uncertainty relation. 2. Relevant equations N/A 3. The attempt at a solution So, right now I am just stuck on part 1. The spherical harmonic for the ground-state is just a constant, which makes me believe the expectation value for the angular momentum should be zero. Can anyone confirm if this is correct?