Question

A car skids to a stop, leaving four skid marks with an average length (D) of 60 feet. The road is asphalt. Skid tests reveal a drag factor(f) of 0.75. Since all four wheels were braking, the braking efficiency (n) is 100% or 1.00. To the nearest mile per hour, what was the car’s speed at the time of the accident

Answer 1

(1/2) m v^2 = force * distance = .75 weight * 60 feet
m = weight/g = weight in pounds/32 approx
(1/64) v^2 = .75 * 60
v is in ft/s, convert to mph