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

  9.1 mph

Step-by-step explanation:

Put the numbers in the formula and do the arithmetic.

  s = √(30×drag factor×skid distance×braking efficiency)

  s = √(30×0.90×3.8×0.80) = √82.08 ≈ 9.06

The car was traveling about 9.1 mph before it started skidding.

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