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

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23 July, 19:28

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Tommy Schneider · Answer 1

120 = - 5 x² + 250

5 x² = 250 - 120

5 x² = 130

x² = 130 : 5 = 26

x = √26 = 5.099 s ≈ 5 s

Answer: B) 5 seconds