SOLUTION: A baseball is thrown upward with an initial speed of 69ft/sec. The number of feet s above the ground after t seconds is given by the equation s=-16t^6+69t. When will the baseball b
Question 213153: A baseball is thrown upward with an initial speed of 69ft/sec. The number of feet s above the ground after t seconds is given by the equation s=-16t^6+69t. When will the baseball be 54 feet above the ground? Answer by nerdybill(7384) (Show Source):
You can put this solution on YOUR website! The problem gives you:
s=-16t^6+69t
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Where s = feet above ground
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Now, they would like to know at what time (t) is it when it is 54 feet above the ground. Simply substitute s for 54 and solve for t:
s=-16t^6+69t
54=-16t^6+69t
0=-16t^6+69t-54
0=16t^6-69t+54
Solve by using the quadratic formula. Doing so yields:
t = {3.285, 1.027} (in seconds)
The reason for two answers -- once going up and another time coming down.
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Details of quadratic below:
