SOLUTION: The altitude in feet of a toy rocket t seconds after launch is given by the function S(t) = -16t^2 + 128t. 1. Find the maximum altitude reached by the rocket. 2. How long does

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: The altitude in feet of a toy rocket t seconds after launch is given by the function S(t) = -16t^2 + 128t. 1. Find the maximum altitude reached by the rocket. 2. How long does       Log On


   

Question 182203: The altitude in feet of a toy rocket t seconds after launch is given by the function S(t) = -16t^2 + 128t.
1. Find the maximum altitude reached by the rocket.
2. How long does it take for the rocket to reach this maximum altitude?
Answer by vleith(2983) About Me  (Show Source):
You can put this solution on YOUR website!
If you know calculus, take the first derivative and solve when that is 0.
If all you have at your disposal is algebra, then use a different method.
Find the two points where the toy is 'on the ground (the values for t that result in S(t) = 0.
-16t%5E2+%2B+128t
-16t%28t-8%29
Set that to 0 and find the two values for t. t =0 and t = 8
SO the max point is hallfwya between them (t=4)
Solve S(t) at t=4 to find the max