SOLUTION: Use the verticle height formula to solve the following h= -16t^ + intitial velocity + initial height. A person throws a ball in the air with an initial height of 4 feet and an ini

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Question 696357: Use the verticle height formula to solve the following h= -16t^ + intitial velocity + initial height. A person throws a ball in the air with an initial height of 4 feet and an initial velocity of 40 feet per second. The person catches the ball when it is 3 feet from the ground. how much time is the ball in the air?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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Use the vertical height formula to solve the following h= -16t^ + initial velocity + initial height.
A person throws a ball in the air with an initial height of 4 feet and an initial velocity of 40 feet per second.
The person catches the ball when it is 3 feet from the ground.
how much time is the ball in the air?
:
The equation for this situation:
-16t^2 + 40t + 4 = 3
-16t^2 + 40t + 4 - 3 = 0
-16t^2 + 40t + 1 = 0
Use the quadratic formula:
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+. where
x = t; a = -16; b = 40; c = 1
t+=+%28-40+%2B-+sqrt%2840%5E2-4%2A-16%2A1+%29%29%2F%282%2A-16%29+
:
t+=+%28-40+%2B-+sqrt%281600%5E2+%2B+64+%29%29%2F%28-32%29+
:
t+=+%28-40+%2B-+sqrt%281664+%29%29%2F%28-32%29+
Two solutions
t+=+%28-40+%2B+40.79%29%2F%28-32%29+
t = %28%2B.79%29%2F%28-32%29
t = -.024755; not a reasonable solution
and
t+=+%28-40+-+40.79%29%2F%28-32%29+
t = %28-80.79%29%2F%28-32%29
t = +2.52 seconds is the time it is in the air and caught