Your foot brake must be able to stop your car within when it is travelling at 20 mph.

Your foot brake must be able to stop car within 5.18 m

Explanation:

d is breaking distance.

s is speed in km/h

is coefficient of friction normally 0.8

250 is  constant.

Give the speed in mile first convert it to km/h

speed in km= 20 * 1.60934

s =32.186 km/h

d= 5.18m

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