If an object is thrown upward with an initial velocity of 64

If an object is thrown upward with an initial velocity of 64 ft/sec, its height after t sec is given by h = 64t -16t^2. Find the number of seconds the object is in the air before it hits the ground.

Solution

It\'s at ground level when h = 0.
h = 64t - 16t^2 = 0
t = 0 seconds
t = 4 seconds
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It\'s at ground level at 0 seconds, and returns to ground level after 4 seconds.