Question 146926
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----ptaylor