The solution before revision #19775 of , by Tete. This is not the current version.

Statement

3.5.42∗. [Insert the problem statement]

Solution

From and and the initial conditions and at , we have

The last two equations are parametric equations of a cycloid, which is the trajectory of a point on the rim of a disk of radius that rolls without slipping on the -axis (shown in blue). Its average velocity is in the positive direction. If the initial velocity is in the negative direction, which is perpendicular to the initial force, then the time-dependent force will keep it in a circular orbit (shown in red) as the equation for centripetal force is satisfied.

Answer

[Insert a concise answer or boxed result]