Question

Police use the formula: v = √ 20 L to estimate the speed of a car, v , in miles per hour, based on the length, L , in feet, of its skid marks when suddenly braking on a dry, asphalt road. At the scene of an accident, a police officer measures a car's skid marks to be 109 feet long. Approximately how fast was the car traveling? Round your answer to the nearest tenth (one decimal place) of a unit.

Answer: The car was traveling at approximately ____________ miles per hour.

Answer 1

46.7 mph

Explanation:

The speed can be found by substituting the measured skid length for the variable in the formula.

v = √(20L)

v = √(20×109) = √2180 ≈ 46.7

The car was traveling at approximately 46.7 miles per hour.