Physics Challenge for Teachers and Students; Maret & September Problems

            My lecturer at the Physics Department of UNM uploaded a physics challenge on his Facebook account. The problem is not too difficult I think, and this is the problem.

The Problem(Maret): Downton Abbey

A vertical light rod of length l is pivoted at its top end. A small sphere of mass m and charge +q is attached to the bottom end of the rod. Another small sphere of charge -q is mounted a distance l directly above the pivot point. After a small disturbance, the rod swings back and forth in the vertical plane. Find the period of that motion.
The Problem(September): Know Your ABC's: Take 2

A large equilateral triangle with a side d is drawn on the floor. A very fast ladybug is trying to run along the perimeter of the triangle as fast as possible. If the magnitude of the acceleration of the ladybug cannot exceed a, what is the minimum time tmin required to complete the task?