question_answer

A motor cyclist is going in a vertical circle. What is the necessary condition so that he may not fall down?

Answer:

                The necessary condition that the motor cyclist may not fall down is \[m{{\upsilon }^{2}}/r\ge \] mg i.e., \[\upsilon \ge \sqrt{rg}\]at the highest point and \[\upsilon \ge \sqrt{5gr}\]at the lowest point.