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Postby khukhuma » Thu Mar 18, 2010 11:04 am

Need help with a math question that pertains gravity? Answer the question. You will need to use the formula 4.9t^2 + (v0)t = s, where t is the time in seconds, v0 is the initial velocity, and s is the distance in meters. 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?

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Tatsumaki Senpūkyaku
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Re: calculator

Postby Tatsumaki Senpūkyaku » Thu Mar 18, 2010 11:33 am

19,525 seconds. did i win something? i don't get it.

good luck on the biology practical exam tomorrow.
Last edited by Tatsumaki Senpūkyaku on Thu Mar 18, 2010 1:23 pm, edited 1 time in total.
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Re: calculator

Postby CloudStrife86 » Thu Mar 18, 2010 11:43 am

If you use the quadratic formula:

Code: Select all

x = -b +- sqrt(b^2 - 4ac)

you get 9.186655866 = 9.19 seconds

my working:
t = -40 + sqrt(40^2 - (4 x 4.9 x -781) = 90.029227484
90.03/9.8 = 9.19

NB. -b - ... gives a negative value, so is discarded.

Moved to off-topic.
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