A footbal quarterback throws a long pass whose height in feet can be modeled by h(t)= -16t^2 + 14t + 11.
When will the ball be at a height of 9 feet?
When will the ball hit the ground?
Thank you very much!!!
+23251 h(t) = -16t2 + 14t + 11
To find when the height is 9': h(7) = 9 ---> -16t2 + 14t + 11 = 9
Subtract 9 from both sides: -16t2 + 14t + 2 = 0
Dividing by -2: 8t2 - 7t - 1 = 0
Factoring: (8t + 1)(t - 1) = 0
Solving: t = -1/8 or t = 1
Negative times are not possible, so the answer is: t = 1 (one second after throwing).
To find when the ball hits the ground: the height will be 0' ---> -16t2 + 14t + 11 = 0
Divide by -1: 16t2 - 14t - 11 = 0
Factoring: (8t - 11)(2t + 1) = 0
Solving: t = 11/8 or t = -1/2
Answer: 1 3/8 second after throwing.
