Problema Solution
A police officer measures a skid at 150 feet long the driver said he was going 45 miles per hour question is how long is the skid mark have to be at 45 miles per hour
Answer provided by our tutors
speed = √(30*CD*length)
where CD is a constant that depends on road conditions (surface, grade, tire condition). For dry level well-traveled asphalt, CD may be taken to be 0.68.
Solving for skid length, we get
length = speed^2/(30*CD) = speed^2/20.4
For 45 mph, this amounts to
length = 45^2/20.4 ≈ 99.3
At the reported speed, the skid marks would be expected to be 99 feet or less on dry level pavement