SOLUTION: The stopping distance d of a car after the breaks are applied varies directly as the square of the speed r. If a car traveling 40 mph can stop in 90 ft, how many feet will it take

Question 517035: The stopping distance d of a car after the breaks are applied varies directly as the square of the speed r. If a car traveling 40 mph can stop in 90 ft, how many feet will it take the same car to stop when it is traveling 60mph?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
The stopping distance d of a car after the breaks are applied varies directly as the square of the speed r.
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d = k*r^2
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If a car traveling 40 mph can stop in 90 ft, how many feet will it take the same car to stop when it is traveling 60mph?
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Solve for "k" using "a car traveling 40 mph can stop in 90 ft":
90 = k*40^2
k = 90/40^2
k = 0.0563
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Equation:
d = 0.0563*r^2
how many feet will it take the same car to stop when it is traveling 60mph?
d = 0.0563*60^2 = 202.5 feet
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Cheers,
Stan H.

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