SOLUTION: if a projectile is fired straight upward from the ground with an initial speed of 40 ft per second,neglecting air resistance,its height s (in feet) above t seconds after projection
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Question 1123040: if a projectile is fired straight upward from the ground with an initial speed of 40 ft per second,neglecting air resistance,its height s (in feet) above t seconds after projection is given by s=-16t^2+40t. which equation should be used to determine the time at which the height of the projectile reaches 40ft? Answer by ikleyn(52788) (Show Source):
The equation you are asking for is
s(t) = 40, or
-16t^2 + 40t = 40.
But the problem is that this equation has NO real solutions, and maximal height of the projectile is only 25 ft, so it will NEVER reach 40 ft height.
Plot s(t) =
