A firecracker shoots up from a hill 140 feet high with an initial speed of 100 feet per second. Using the formula H (t) = - 16t2 + vt + s, approximately how long will it take the firecracker to hit the ground?

5 seconds

7 seconds

9 seconds

11 seconds

Question

3 April, 19:38

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Answers (1)

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Edward Potter · Answer 1

H (t) = - 16t^2 + vt + s

0 = - 16t^2 + 100t + 140

4t^2 - 25t - 35 = 0

t = 7 seconds.

A firecracker shoots up from a hill 140 feet high with an initial speed of 100 feet per second. Using the formula H (t) = - 16t2 + vt + s, approximately how long will it take the firecracker to hit the ground?5 seconds7 seconds9 seconds11 seconds