5. A fireworks mortar is shot straight upward with an initial velocity of 176 ft/sec from a
platform 4 ft off the ground.
a. Use the formula s = —1/2gt² +vot + so to write a model for the height of the mortar s (in ft) at t seconds after launch.

b. How long will it take the mortar, on the way up, to reach a height of 100 ft.? Round
to two decimal places. Show all work. Answer with a complete sentence.