To a police investigator, skid marks evidence is extremely important in determining how vehicles moved in a collision. Skid mark

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2 months ago

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To a police investigator, skid marks evidence is extremely important in determining how vehicles moved in a collision. Skid mark

s are the equivalent of fingerprints 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 equals square root of 30 times D times f times n end root

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

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.

40

34

37

30

Mathematics

1 answer:

Svet_ta [12.7K] · Answer 1 · 2026-03-12T08:37:04+03:00

The given formula for calculating the speed of a car is:

$S=\sqrt{30\times D\times f\times n}$

Where: S = speed in miles per hour

30 = a constant value in the equation

D = length of the skid marks in feet

f = drag factor for the road surface

n = braking efficiency expressed as a percentage

In this scenario, we know the average skid length is 60 feet, so D=60.

The Drag Factor is noted as f=0.75.

Additionally, the braking efficiency is 100% or n=1.

Plugging these values into the speed formula yields:

$S=\sqrt{30\times 60\times 0.75\times 1} =\sqrt{1350}=\sqrt{36.74} \approx37$ miles per hour.

Among the provided options, the third option, which indicates 37, is correct.