1. The problem statement, all variables and given/known data For a given angular momentum L, find the potential energy function U(r) that leads to a spiral path of the form r=r0θk. Choose the total energy E to be zero. Hint: obtain an expression for r' that is only a function of r, not θ, and then use the energy equation with effective potential 2. Relevant equations E=.5μ(r')2+(L2/2μr2)+U(r) r=r0θk 3. The attempt at a solution I can't seem to figure out where to start. I don't want a full solution, but if someone could point me in the right direction, I will try to solve it from there.