document.write( "Question 464009: The stopping distance d of a car after the brakes are applied varies directly as the square of the speed r. If a car travelling 30 mph can stop in 50 ft, how many feet will it take the same car to stop when it is travelling 20 mph? \n" ); document.write( "
Algebra.Com's Answer #317837 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
The stopping distance d of a car after the brakes are applied varies directly as the square of the speed r.
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\n" ); document.write( "d = kr^2
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\n" ); document.write( "Solve for \"k\" using \"a car travelling 30 mph can stop in 50 ft\"
\n" ); document.write( "50 = k*30^2
\n" ); document.write( "k = 50/900
\n" ); document.write( "k = 0.0556
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\n" ); document.write( "Equation:
\n" ); document.write( "d = 0.0556*r^2
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\n" ); document.write( "\n" ); document.write( "How many feet will it take the same car to stop when it is travelling 20 mph?
\n" ); document.write( "d = 0.0556*20^2
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\n" ); document.write( "distance = 22.22 ft
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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