# An object is launched from the ground. The object’s height, in feet, can be described by the quadratic function h(t)

An object is launched from the ground. The object’s height, in feet, can be described by the quadratic function h(t) = 80t – 16t2, where t is the time, in seconds, since the object was launched. When will the object hit the ground after it is launched? Explain how you found your answer.

Set h(t), time = 0.
0 = 80t-16t^2
-16t^2+80t =0
Factor
-16t(t-5) =0
t =0 (when launched)
& t = 5
Sample Response: The object will hit the ground after 5 seconds. You can rewrite the quadratic function as a quadratic equation set equal to zero to find the zeros of the function 0 = –16t2 + 80t + 0. You can factor or use the quadratic formula to get t = 0 and t = 5. Therefore, it is on the ground at t = 0 (time of launch) and then hits the ground at t = 5 seconds.
What did you include in your response? Check all that apply.
I Rewrite the quadratic function as a quadratic equation set equal to zero: 0 = –16t2 + 80t + 0.
Use the quadratic formula to solve for the zeros.
Factor to solve for the zeros.
t = 0 and t = 5 seconds.
The object will hit the ground after 5 seconds.