During the investigation of a traffic accident, police find skid marks 90.0 m long. They determine the coefficient of friction between the car's tires and the roadway to be 0.500 for the prevailing conditions. Estimate the speed of the car when the brakes were applied.

Newton's three laws:
Newton's first law: Every object continues in its state of rest, or of uniform velocity in a straight line, as long as no net force acts on it.
Newton's second law: The acceleration of an object is directly proportional to the net force acting on it, and is inversely proportional to its mass. The direction of the acceleration is in the direction of the net force acting on the object.
Newton's third law: Whenever one object exerts a force on a second object, the second exerts an equal force in the opposite direction on the first.