It's been a while since I have gone through my physics classes so help me out if you would. While investigating a traffic accident we found skid marks that were 24.9 m in length. The mass of the car was around 1250 kg. After the accident reconstructionist used his "sled" the coefficient of friction was 0.836. What was the initial velocity of the car? From what I remember if unknown variable such as the time or acceleration would make this problem easy. Hopefully I will be able to go to the reconstructionist school and learn the things specific to accidents. I'm not sure how to go about finding the velocity. Can anyone help?