An observation deck extends 202 feet out above the valley. The deck sits 152 feet above the valley floor. If an object is dropped from the observation deck, it's height h in feet, after t seconds, is given by h= -16t^2+152. How long will it take for the object to be 8 feet above the valley floor?

Respuesta :

Answer:

3 secs

Step-by-step explanation:

Given the height of the object as it drops from the observation deck expressed as;

h= -16t^2+152

To determine the the time it will take the object to be 8 feet above the valley floor, we will substitute h = 8 into the equation and calculate t as shown;

8 = -16t^2+152

subtract 8 from both sides

8-8 = -16t^2+152-8

0 =  -16t^2+144

0-144 =  -16t^2

-144 = -16t^2

16t^2 = 144

Divide both sides by 16;

16t^2/16 = 144/16

t^2 = 9

t = √9

t = 3seconds

Hence it will take 3 seconds for the object to be 8 feet above the valley floor