Answer:
Step-by-step explanation:
Initial Velocity of projection = 89ft/sec
height(ft), t seconds after launching is given by s=-16t^2 + v0t + s0
A) time the projectile will reach a height of 100 ft
s=-16t^2 + v0t
v0 = 89ft/sec
s = 100ft
100 = - 16t² + 89t
-16t² + 89t - 100 = 0
Using the online quadratic equation solver;
t = 4s or t = 1.5625