Question

9) A policeman investigating an accident measures the skid marks left by a car. He determines that 9) the distance between the point that the driver slammed on the brakes and the point where the car came to a stop was 28.0 m. From a reference manual he determines that the coefficient of kinetic friction between the tires and the road under the prevailing conditions was 0.300. How fast was the car going wh~er applied the brakes? (This car was not equipped with anti-lock brakes.)

Answer 1

Answer:

Explanation:

Provided the car did not collide with anything during its slide,

Kinetic energy will convert to work of friction

½mv² = Fd

½mv² = μmgd

       v = √(2μgd)

       v = √(2(0.300)(9.81)(28.0))

       v = 12.8377...

       v = 12.8 m/s