Question

An object is thrown upward from the top of an 80ft tower.
The height h of the object after t seconds is represented by the quadratic equation h= -16t^2 + 64t + 80.

After how many seconds will the object hit the ground?

A. 29 seconds
B. 6.4 seconds
C. 5.0 seconds
D. 8.0 seconds

Answer 1

C because if you solve for the solutions for the quadratic, then you get 5 and -1 but you cant have negative seconds so 5 is the right answer!