Question 724396:  A ball is thrown upward with an initial velocity of 343 m/sec.  When will it be 4900 meters high?  I have been trying to help my son with his Algebra.  I am having such a hard time.  Could some one please show and explain to me an eqation to figure this problem out? 
 Answer by Alan3354(69443)      (Show Source): 
You can  put this solution on YOUR website! A ball is thrown upward with an initial velocity of 343 m/sec.  When will it be 4900 meters high? 
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The equation for ht vs. time should be given with the problem. 
If not, the commonly used is 
h(t) = -4.9t^2 + vt + C, t in seconds, h & C in meters 
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h(t) = -4.9t^2 + 343t = 4900 
4.9t^2 - 343t + 4900 = 0 
t^2 - 70t + 1000 = 0 
(t - 20)*(t - 50) = 0 
t = 20 seconds going up 
t = 50 seconds falling 
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That's a good throw, ~ 767 mi/hr 
 
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