Question

You are riding a roller coaster when a shoe falls off your foot. The function y=200−16t^2 represents the height y (in feet) of the shoe t seconds after it falls off your foot. The shoe lands on the top of a 31-foot-tall building. After how many seconds does the shoe hit the building?

Answer 1

A graphing calculator shows it takes 3.25 seconds for the shoe to hit the building.

_____
200 -16t^2 = 31
169 = 16t^2
√(169/16) = t
t = 13/4 = 3 1/4