Can some explain how to do this problem? I tried using derivatives...but...I keep getting a different answer from what my teacher told me!

Question

A projectile is fired directly upward with an initial velocity of 144 ft/sec and its height (in feet) above the ground after t seconds is given by s(t). Find the (a) the velocity and acceleration after t seconds (b) the maximum height and (c) the duration of the flight.

s(t)= 144-16t^2

Answer 1

Your equation is wrong.

s(t)=144t-16t^2
s'=velocity=144-32t
s"=acceleration=-32ft/s^2

Now try it.