Question 965909
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For 20 mph:
{{{D=(1/16)x^2}}}={{{(1/16)20^2)=1/16(400)}}}={{{25ft}}}
ANSWER 1: The braking distance at 20 mph is 25 feet.
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For 60 mph:
{{{D=(1/16)60^2}}}={{{(1/16)3600=225ft}}}
ANSWER 2: The braking distance at 60 mph is 225 feet.
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If the distance is 25 feet, speed is 20 mph. (See ANSWER 1)
-OR-
{{{D=(1/16)x^2}}}
{{{16D=x^2}}}
{{{x=sqrt(16D)}}}={{{4(sqrt(D))}}} Plug in value for D and solve.