Quadratic Equation

Question

An object is thrown upward from the top of a 160-foot building with an initial velocity of 144 feet per second. The height h of the object after t seconds is given by the quadratic equation h=−16t^2+144t+160. When will the object hit the ground?

Answer 1

Set the equation equal to zero and solve for x:

 

-16t² + 144t + 160 = 0  divide by -16

 

t² - 9t - 10 = 0

(t-10)(t+1)=0

 

t = 10 or -1, only a positive answer makes sense so t=10 secs