Problema Solution
An arrow is fired straight up from the ground with an initial velocity of 160 feet per second. Its height, s(t), in feet at any tie t is given by the function s(t)=-16t^2 + 160t. Find the interval of time for which the height of the arrow is greater than 144 feet.
Answer provided by our tutors
s(t)=-16t^2 + 160t
ds(t)/dt = -32t+160
160 = -32t+160
so t = 0
so hence prove it
velocity = -32t+160 , at t=0
= 160 which is greater