Question

An object is thrown downward with an initial velocity of 4 feet per second. The relationship between the distance s it travels and time t is given by s = 4t + 16t2. How long does it take the object to fall 72 feet?

Answer 1

4t + 16t^2 = 72
4t^2 + t - 18 = 0
(t-2)(4t+9) = 0
t = 2