Question

Fredrick threw a ball from the top of a building. The height of the ball, in feet, after it is thrown is modeled by the function h(t) = -16t^2 +64t + 100, where represents time, in seconds.
Approximately how long did it take the ball to reach the ground (h = 0)?
A. 1.2 seconds
B. 3.5 seconds
C. 4.0 seconds
D. 4.5 seconds
E. 5.2 seconds

Answer 1

Answer:

• E. 5.2 seconds

Step-by-step explanation:

Need to find the value of t, when h(t) = 0

• -16t^2 +64t + 100 = 0
• 4t^2 - 16t - 25 = 0
• 4t^2 - 2*2t*4 + 16 = 41
• (2t - 4)^2 = 41
• 2t - 4 = √41
• 2t - 4 = 6.4
• 2t = 10.4
• t = 5.2

Answer is 5.2 seconds