SOLUTION: The height h, in feet, of a stone thrown with an upward speed of 40 ft/s is given by the formula h=40t-16t^2, where t is the time, in seconds, since the stone was thrown. How long

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Question 180859: The height h, in feet, of a stone thrown with an upward speed of 40 ft/s is given by the formula h=40t-16t^2, where t is the time, in seconds, since the stone was thrown. How long does it take the stone to reach the highest point of its path of motion?
Answer by rapaljer(4671) About Me  (Show Source):
You can put this solution on YOUR website!
Rewrite this equation as

h =-16t^2 + 40t

It is well-known that the highest point on a parabolic graph y=ax^2 +bx +c occurs at the value of x+=+-b%2F%282a%29.

In this equation for h=-16t^2 + 40t, the maximum value of h occurs when
t=-b%2F%282a%29+
t=%28-40%29%2F%282%2A-16%29+
t=%28-40%29%2F%28-32%29
t=10%2F8=5%2F4 seconds

R^2