Question

If a football player passes a football from 4 feet off the ground with an initial velocity of 36 feet per second, how long will it take the football to hit the ground? Use the equation h = -16t2 + 36t + 4.

A. quantity of 9 plus or minus square root of 65 all over 8
B. 9 plus or minus square root of 65 end root over 8
C. quantity of 9 plus or minus square root of 97 all over 8
D. 9 plus or minus square root of 97 end root over 8

Answer 1

D ) h₁,₂ =[ ( 9 ± √97 ) ]/8

Explanation:

The equation of the football is

h = -16t² + 36t +4

What is the time for football to hit the ground

Hit the ground means h = 0 then

-16t² + 36t + 4 = 0

Simplifying by (-4)

4t² - 9t - 1 = 0 a second degree equation

Solving

h₁,₂ =[ ( 9 ± √(81 + 16) ] /8 ⇒ h₁,₂ =[ ( 9 ± √97 ) ]/8

The answer given in D