Question

The quadratic model f(x) = –5x2 + 200 represents the approximate height, in meters, of a ball x seconds after being dropped. The ball is 50 meters from the ground after about how many seconds?

2.45
3.16
5.48
7.07

Answer 1

Set -5x^2 + 200 = 50.
-5x^2 = -150 → x^2 = 30 → x = √30 ≈ 5.48 seconds.

Answer: 5.48