Algebra: Quadratic Functions
posted by Isiah on .
A model rocket is launched with an initial velocity of 128 ft/s from a height of 70 ft. The height of the rocket, in feet, t seconds after it has been launched is given by the function s(t)=−16t^2+128t+70. Determine the time which the rocket reaches its maximum height and find the maximum height.

16 t^2 + 128 t = s  70
t^2 8 t = s/16 + 4.375
t^2  8 t + 16 = s/16 + 20.375
(t4)^2 = (1/16) (s  326)
vertex at time = 4 and height = 326