A professor uses a video camera to record the motion of an object falling from a height of 250 meters. The function f(x) = –5x2 + 250 can be used to represent the approximate height of the object off the ground after x seconds. Which is the best estimate for the amount of time elapsed when the object is 120 meters off the ground? 4 seconds 5 seconds 6 seconds 7 seconds
(The answer is 5 seconds)
