SOLUTION: Can anyone help me please, thanks a lot Suppose Charlie O達rian of the braves hits a baseball straight upward at 150 ft/sec from a height of 5 ft. Use the formula to determine how

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Question 162802: Can anyone help me please, thanks a lot
Suppose Charlie O達rian of the braves hits a baseball straight upward at 150 ft/sec from a height of 5 ft. Use the formula to determine how long it takes the ball to return to the earth.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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Suppose Charlie O達rian of the braves hits a baseball straight upward at 150 ft/sec from a height of 5 ft. Use the formula to determine how long it takes the ball to return to the earth.
:
Let t = time in seconds
:
The formula has 3 parts,
gravity, -16t^2; negative because it pulls downward
upward velocity, 150t positive because it's going upward
initial height, 5 ft; it starts from 5 ft above the ground
:
The formula
h = -16t^2 + 150t + 5
:
When it returns to earth h = 0, therefore:
-16t^2 + 150t + 5 = 0
:
We have to use the quadratic formula to solve for t:
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
In this problem: a=-16; b=150; c=5
t+=+%28-150+%2B-+sqrt%28150%5E2+-+4%2A-16%2A5+%29%29%2F%282%2A-16%29+
:
t+=+%28-150+%2B-+sqrt%2822500+%2B+320+%29%29%2F%28-32%29+
:
t+=+%28-150+%2B-+sqrt%2822820%29%29%2F%28-32%29+
:
We want the positive solution here:
t+=+%28-150+-+151%29%2F%28-32%29+
t = %28-301%29%2F%28-32%29
t = + 9.4 sec to return to earth