Question

How do I solve this word problem?

When a car slams on its brakes and starts to skid, it leaves skid marks on the road. Investigators use these marks to determine how fast a car was going when it started to brake. The car's speed, `v` (in feet per second) is related to the skid mark length, `d` , (in feet) by the equation `v=√32fd`

v=32fd, where
`f` is the coefficient of friction determined by the material the car was skidding on.

Wet asphalt has a coefficient of friction of 0.5. If a car was driving 25 miles per hour and slams on its brakes, how long of a skid mark will it leave? 1 mile = 5280 feet.

Answer 1

The given equation tells the relationship between the velocity and the length of skid mark,so simply by putting the given values,we can determine the length of the skid mark.

Given, `v= 25` miles/ hrs=`25*(5280/3600) (ft)/s` i.e `36.67 (ft)/s`

`f = 0.5`

So,from the equation,we get the length of the skid mark=`d= 36.67/(sqrt(32)*0.5)` i.e `12.98 ft`