Answer: Days and nights are equal in length everywhere.
Explanation:
Equinox means equal night. There are two equinox - vernal equinox and autumnal equinox. When the sun crosses celestial equator, the sun rays fall directly over equator at noon. Thus, there is equal length of day and night in the two hemisphere. It occurs around March 22 and September 22.
The tension in the string with friction would be the biggest because of the involvement of the force of gravity. This would result in that the friction force that is acting on the system. There is no friction in the frictionless system, and only the force of gravity is relevant.