Here is the problem: During an investigation of a traffic accident, the highway
ID: 1695403 • Letter: H
Question
Here is the problem:During an investigation of a traffic accident, the highway patrol finds skid marks 40.0 m long. The investigator determines t he coefficient of friction between the car's tires and the roadway to be 0.650 for the prevailing conditions. Estimate the initial speed of the car when the brakes locked up the tires and started skidding.
If I knew the mass of the car I could figure out the normal force (f=un), and then the frictional force which would allow me to find the negative acceleration, right? Can I do this problem without any more information given?
Explanation / Answer
coefficient of friction (mu) = 0.65
the acceleration -a = (mu)g = 0.65*9.8 = 6.37m/s2
final speed vf =0
the distance d = 40m
intial speed = ?
vf2 =vi2+2ad
vi2=2*6.37*40 = 509.6
vi = 22.57m/s