Problema Solution
A toy rocket was launched from the ground straight up with an initial velocity of 144 ft/sec. How mawny seconds after launch was the rocker 128 feet above the ground?
Answer provided by our tutors
s(t) = -16t^2+192t = 0
-16t=-192
t=192/16 = 12 seconds
s(t)=-16t^2+144t
-16t^2 = -144t
16t =144
t = 9 seconds