Now that you know the total skid distance (3.8 ft), use the skid-distance formula to find how fast the car was going before it started skidding. How fast was the car traveling before it started skidding? s= sqrt (30 * drag factor * skid distance * braking efficiency)
s= speed
drag factor= 0.90
skid distance= 3.8
braking efficiency= 80% or 0.80