1. The problem statement, all variables and given/known data A thin plastic rod of length L with total charge +q uniformly distributed along only the outer half-length is shown in Fig. 1. The rod is rotated at a constant angular speed w rad/sec about, and perpendicular to, the z-axis. Find the magnetic field B at the pivot, perpendicular to the plane of rotation in terms of L, q and w. (Hint: View the situation as a series of concentric current loops, each with thickness dl.) 2. Relevant equations No clue which equations will help with angular velocity. 3. The attempt at a solution I don't know how to go about this problem Thanks for any help.