Jack and a Jill are standing on flat ground in front of an empty well that extends a depth s below the ground. Jill tosses a penny down the well with an initial velocity u0, while Jack decides to toss a penny up with an initial velocity v0.

Question

How long does it take for Jack and Jill’s pennies to hit the bottom of the well? Express your answer in terms of know quantities such as v0, u0, s, and g, where g is the acceleration due to gravity.