<PRE><B>Question 440852</B>
A Ball is thrown upward from a height of 15 ft. with an initial upward velocity of 5 ft a sec. Use the formula h=-16t squared+vt+s to find out how long it will take for the ball to hit the ground?
---------------------
h=-16t squared+vt+s
h(t) = -16t^2+5t+15
---
Height is zero when the ball hits the ground:
---
Solve: -16t^2+5t+15 = 0
---
Use Quadratic Formula:
t = [-5 +- sqrt(25-4*-16*15)]/(-32)
-----
t = [-5 +- sqrt(985)]/(-32)
---
Positive solution:
t = [-5-31.38]/(-32)
t = 1.1370 seconds
=========================
Cheers,
Stan H.
 </PRE>