To a police investigator, skid marks evidence is extremely important in determining how vehicles moved in a collision. skid marks are the equivalent of a fingerprint in a criminal investigation, and just as important. the speed a car was traveling can be calculated using the skid marks made as the car came to a stop. the formula for finding the speed of the vehicle is:
s =
where:
s = speed in miles per hour
30 = a constant value used in the equation
d = length of the skid marks in feet
f = drag factor for the road surface
n = braking efficiency as a percent.
be sure to use the square root function on your calculator for this problem.
a) a car skids to a stop, leaving four skid marks with an average length (d) of 60 feet. the road is asphalt. skid tests reveal a drag factor (f) of 0.75. since all four wheels were braking, the braking efficiency (n) is 100% or 1.00. to the nearest mile per hour, what was the car’s speed at the time of the accident? 37 mph
i need with b anyone

b) does doubling the length of the skid mark double the speed the car was going? if the car leaves four skid marks with an average length (d) of 120 feet, does the car’s speed at the time of the accident double? use the same drag factor and braking efficiency from part a. use the car’s speed that you calculated in part a to justify your answer.