SOLUTION: Problem #36(this problem is driving me crazy among two other ones more)
A ball is thrown upward from the roof of a building 100m tall with an initial velocity of 20m/s. Use this
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A ball is thrown upward from the roof of a building 100m tall with an initial velocity of 20m/s. Use this
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Question 77326: Problem #36(this problem is driving me crazy among two other ones more)
A ball is thrown upward from the roof of a building 100m tall with an initial velocity of 20m/s. Use this information for exercises 35 to 38.Please show all your steps and the answer in radical form.
The equation for the hieght of the ball is: h = -5t^2+20t+100
When will the ball reach a height of 80m? Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! h = -5t^2+20t+100
When will the ball reach a height of 80m?
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80 = -5t^2+20t+100
-5t^2+20t+20=0
t^2-4t-4=0
t=[4+sqrt(16-4*-4]/2
t=[4+sqrt(32)]/2
t=[4+4sqrt2]/2
t=2+2sqrt2 seconds
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Cheers,
Stan H.
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