Quadratic Equation

Question

An object is dropped from 21 feet below the tip of the pinnacle atop a 505-ft tall building. The height h of the object after t seconds is given by the equation h equals negative 16 t squared plus 484h=−16t2+484. Find how many seconds pass before the object reaches the ground.

Answer 1

height, h = -16t² + 484

 

when it hits the ground, h = 0

 

0 = -16t² + 484

 

t² = 484/16 = 30.25

 

hence t = 30.25^1/2 = 5.5 seconds