SOLUTION: A stone is projected vertically upwards and its height in meters after T seconds is given by h=50t-t^2. Find the time taken for the stone to first reach a height of 120meters.
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Question 792713: A stone is projected vertically upwards and its height in meters after T seconds is given by h=50t-t^2. Find the time taken for the stone to first reach a height of 120meters.
I used the quadratic equation to find t but i didnt make it i got stuck when i used the cross method to find the factors, please help me...thankyou Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! A stone is projected vertically upwards and its height in meters after T seconds is given by h=50t-t^2. Find the time taken for the stone to first reach a height of 120meters
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Solve:: 50t-t^2 = 120
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t^2 - 50t + 120 = 0
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t = [50 +- sqrt(2500-4*120)]/2
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t = [50 +- sqrt(2020)]/2
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t = [50 +- 44.94]/2
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Smallest positive value of "t":
t = 2.5278 seconds
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Cheers,
Stan H.
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