SOLUTION: Solve: If an object is thrown upward with an initial velocity of 64 ft/sec, its height after t sec is given by h = 64t - 16t2. Find the number of seconds the object is in the ai

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Question 144915: Solve:
If an object is thrown upward with an initial velocity of 64 ft/sec, its height after t sec is given by h = 64t - 16t2. Find the number of seconds the object is in the air before it hits the ground.


Answer by nabla(475) About Me  (Show Source):
You can put this solution on YOUR website!
0=64t-16t^2
0=-16t(t-4)
Implies t=0 or t=4.
We exclude t=0, leaving t=4 the only solution.

Check:
64(4)-16(4^2)=256-256=0.