Suppose that a bottle rocket is launched upward with a initial velocity of 96ft/sec from a height of 880ft. Its height is h, in feet, after t seconds is given by h(t)=-16^2 + 96t + 880. After how long will the rocket reach the ground?
When rocket hits ground , height =0
0 = -16 t2 + 96t + 880 Quadratic formula to find t.... throw out negative t value
-16t^2 + 96t + 880 = 0 multiply through by -1
16t^2 - 96t - 880 = 0 divide through by 16
t^2 - 4t - 55 = 0 factor
(t - 11) ( t + 5) = 0
The first factor set to 0 and solved for t will give us the answer
t - 11 = 0
t = 11 seconds
