SOLUTION: The height of a projectile fired upward with an initial velocity if 400 feet per second is given by the formula h=-16t^2+400t, where h is the height in feet and t is the time in se

Question 988387: The height of a projectile fired upward with an initial velocity if 400 feet per second is given by the formula h=-16t^2+400t, where h is the height in feet and t is the time in secounds. Find the time required for the projectile to return to earth.
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
Find the time to the highest point and double it.
That is the vertex of a quadratic equation, which x value (t here) is -b/2a=-400/-32=12.5
So the vertex is at 12.5 seconds, and the time to Earth is 25 seconds.
The maximum height will be 2500 feet.

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