SOLUTION: An object is thrown upward from the top of a 96 foot building with an initial velocity of 80 feet per second. The height h of the object after t seconds is given by the quadratic e

Algebra ->  Rectangles -> SOLUTION: An object is thrown upward from the top of a 96 foot building with an initial velocity of 80 feet per second. The height h of the object after t seconds is given by the quadratic e      Log On


   

Question 967989: An object is thrown upward from the top of a 96 foot building with an initial velocity of 80 feet per second. The height h of the object after t seconds is given by the quadratic equation h = -16t^2+80t+96. When will the object hit the ground?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
There is only 1 time when the object is on the ground,
and that is when +h+=+0+
+h+=++-16t%5E2+%2B+80t+%2B+96+
+0+=++-16t%5E2+%2B+80t+%2B+96+
Divide through by +16+
++-t%5E2+%2B+5t+%2B+6+
+%28+-t+%2B+6+%29%2A%28+t+%2B+1+%29+=+0+
+t+=+6+ ( time must be positive so, +t+ can't be +-1+ )
------------------
the object will hit the ground in 6 sec
Here's the plot:
+graph%28+400%2C+400%2C+-2%2C+7%2C+-50%2C+200%2C+-16x%5E2+%2B+80x+%2B+96+%29+