Answer:
Step-by-step explanation:
Give the height of the observation deck modeled by the equation
h= -16t^2+149 where t is in seconds;
To get the time it will take the object to be 5 feet above the valley floor, we wil substitute h = 5ft into the modeled equation and calculate t;
h= -16t^2+149
5= -16t^2+149
-16t^2 = 5-149
-16t^2 = -144
t² = 144/16
t² = 9
t = √9
t = 3secs
Hence the time it will take for the object to be 5 feet above the valley floor is 3secs