| 
 
 
| 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? -------------------
 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
 --------
 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
 =======================
 That's a good throw, ~ 767 mi/hr
 
 | 
  
 | 
 |