Step-by-step explanation:
Given that, the height of an object tossed upward with an initial velocity of 136 feet per second is given by the formula :

Where
h is the height in feet
t is the time in seconds
Let t is the time required for the object to return to its point of departure. At this point, h = 0

t = 8.5 seconds
So, the time required for the object to return to its point of departure is 8.5 seconds.