SOLUTION: I'm not sure how to do this problem... In a physics experiment, a ball is dropped off a 144-ft platform. The height of the ball above the ground is given by the equation h=-16

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Question 245930: I'm not sure how to do this problem...
In a physics experiment, a ball is dropped off a 144-ft platform. The height of the ball above the ground is given by the equation h=-16t^2+144
where h is the ball's height in feet, and t is the time in seconds after the ball is dropped (t is > or = 0)
Find the time required for the ball to hit the ground.(Let h =0)
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
In a physics experiment, a ball is dropped off a 144-ft platform. The height of the ball above the ground is given by the equation h=-16t^2+144
where h is the ball's height in feet, and t is the time in seconds after the ball is dropped (t is > or = 0)
Find the time required for the ball to hit the ground.(Let h =0)
:
-16t^2 + 144 = 0
simplify and change the signs, divide by -16
t^2 - 9 = 0
t^2 = 9
t = sqrt%289%29
t = 3 sec to hit the ground
:
:
Check this
-16(3^2) + 144 =
-16(9) + 144 =
-144 + 144 = 0