3. Consider the motorcyclist riding on the inside of a vertical circle of radius b. His initial speed at the bottom of the circle is u. a) Explain why the three domains (i) u^2 < 2gb, (ii) 5gb > u^2 > 2gb and (iii) u^2 > 5gb are qualitatively different. b) Describe what happens in domain (ii). Give a sketch of the trajectory, indicating the height h where the rider is released from the hoop. Calculate h(u). So for (a) I said that the domains are the speed of the motorcyclist at different points along the circle, domain i being the top of the track since speed would be smallest, domain being the bottom where speed is greatest, and domain ii being everywhere else. Would I be correct in saying this? For (b), if my explanation above is correct then I know what happens in domain ii, where gravity affects the speed of the motorcyclist in such a way that it decreases his speed as he travels from the bottom to the top and increases it as he goes back from the top to the bottom. I'm just confused on the wording of the rest of (b) and not sure how to approach solving this since I thought the rider is in a closed hoop so how can he be released from it. Am I not reading the problem correctly?