Question 130784: If a rock falls from a height of 40 meters on Earth, the height H (in meters) after x seconds is approximately
H(x) = 40 - 4.9x2.
When does the rock strike the ground? Round to the nearest hundredth, if necessary.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! If a rock falls from a height of 40 meters on Earth, the height H (in meters) after x seconds is approximately
H(x) = 40 - 4.9x2.
When does the rock strike the ground? Round to the nearest hundredth, if necessary.
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Let H(x) = zero and solve for "x".
40 - 4.9x^2 = 0
4.9x^2 = 40
x^2 = 40/4.9
x^2 = 400/49
x = 20/7
x = 2.857...
Cheers,
Stan H.
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