Question 433080
The stopping distance d of a car after the brakes are applied varies directly as the square of the speed r. If a car traveling 60 mph can stop in 200 ft, how many feet will it take the same car to stop when it's traveling 70 mph?

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d = k(r^2)
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Solve for "k" using "a car traveling 60 mph can stop in 200 ft".
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200 = k(60)^2
k = 200/3600 = 1/18
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Equation:
d = (1/18)r^2
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How many feet will it take the same car to stop when it's traveling 70 mph?
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d = (1/18)(70^2)
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d = (1/18)4900
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distance = 272.22 ft
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Cheers,
Stan H.