A car traveling at 60 mph requires 200 ft to stop So if it i

A car traveling at 60 mph requires 200 ft to stop. So if it is traveling at 100 mph how many ft does it take to stop. I have tried cross multiplication and keep coming to 333.33 ft. The answer I have for the problem is 556 ft. Please help. Thanks!

Solution

Cross multiplying doesn\'t work because it\'s not a linear relationship.
Braking Distance on level pavement is given by the formula:
d=v^2/2gf where:
d=braking distance
v=speed of the car
g=acceleration due to gravity (32.2 ft/sec^2)
f=coefficient of friction between tires and road
Using the data that\'s given, we have:
200=60^2/64.4f multiply each side by 64.4f
12,880f=3600 divide each side by 12,880
f=0.2795----coefficient of friction between tires and road
Using the formula again, we have:
d=100^2/(64.4*0.2795)=
d=10,000/17.9998=555.562 ft
Hope this helps