SOLUTION: You will need to use the formula 4.9t2 + vot = s. A ball is thrown downward at a speed of 40 meters per second (v0) from an altitude of 781 meters. Approximately how long does i

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: You will need to use the formula 4.9t2 + vot = s. A ball is thrown downward at a speed of 40 meters per second (v0) from an altitude of 781 meters. Approximately how long does i      Log On


   



Question 233415: You will need to use the formula 4.9t2 + vot = s.
A ball is thrown downward at a speed of 40 meters per second (v0) from an altitude of 781 meters. Approximately how long does it take to reach the ground?
i solved it to be t=9.19seconds using the quadratic formula

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
use the formula 4.9t2 + vot = s.
A ball is thrown downward at a speed of 40 meters per second (v0) from an altitude of 781 meters. Approximately how long does it take to reach the ground?
i solved it to be t=9.19seconds using the quadratic formula
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-4.9t^2 - 40t + 781 = 0
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t = [40 +- sqrt(40^2 - 4*-4.9*781)]/(2*-4.9)
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t = [40 +- sqrt(16907.6)]/(
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t = [40 +- 130.029]/(-9.8)
Positive solution:
t = (40-130.029)/-9.8
t = 9.19 seconds
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You have it right.
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Cheers,
Stan H.