Hello I am stuck and confused by this question

A toy rocket fired straight up into the air has height s(t) = 144t - 16t feet after t seconds. a. What is the rocket's initial velocity (when t = 0)? b. What is the velocity after 3 seconds? c. What is the acceleration when t = 8? d. At what time will the rocket hit the ground? e. At what velocity will the rocket be traveling just as it smashes into the ground? a. The rocket's initial velocity is ft/sec. b. After 3 seconds, the velocity of the rocket is ft/sec. c. When t= 8, the acceleration of the rocket is ft/sec2 . d. The rocket will hit the ground seconds after it is launched. e. When the rocket smashes into the ground, it will be travelling at ft/sec