well life hack is a strategy adopted in order to manage one's time and daily activities in a more efficient way.
life hacks are intended to improve your life e.g setting an alarm clock in order to wake up on time or putting a stoking over the end of your vacuum cleaner to help you find a tiny item etc.
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.
