SOLUTION: A ball is thrown downward from a window in a tall building. Its position at time T in seconds is s=16t^2+32t, where S is in feet. How long (to the nearest tenth) will it take the b

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Question 113224: A ball is thrown downward from a window in a tall building. Its position at time T in seconds is s=16t^2+32t, where S is in feet. How long (to the nearest tenth) will it take the ball to fall 276 feet?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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A ball is thrown downward from a window in a tall building. Its position at time T in seconds is s=16t^2+32t, where S is in feet. How long (to the nearest tenth) will it take the ball to fall 276 feet?
:
The equation:
16t^2 + 32t = 276
:
16t^2 + 32t - 276 = 0
:
Simplify, divide equation by 4
4t^2 + 8t - 69 = 0
:
Find t using the quadratic formula: a = 4; b = 8; c = -69
:
t+=+%28-8+%2B-+sqrt%288%5E2+-+4+%2A+4%2A+-69+%29%29%2F%282%2A4%29+
:
Solve this and the positive solution should be: t = 3.272