As you drive your car along a country road at night, a deer jumps out of the woods and stands in the middle of the road ahead of you. this occurs just as you are passing from a 55-mi/h zone to a 50-mi/h zone. at the 50-mi/h speed-limit sign, you slam on the car's brakes, causing them to lock up, and skid to a stop inches from the startled deer. as you breathe a sigh of relief, you hear the sound of a police siren. the policeman proceeds to write you a ticket for driving 56 mi/h in 50-mi/h zone. because of your preparation in physics, you are able to use the 33.5-m-long skid marks that your car left behind as evidence that you were not speeding. based on your evidence, at what speed were you actually driving? (the coefficient of friction between between automobile tires and dry concrete is 0.80.)

Is a  vector quantity  that refers to "the rate at which an object changes its position." imagine a person moving rapidly - one step forward and one step back - always returning to the original starting position. while this might result in a frenzy of activity, it would result in a zero velocity. because the person always returns to the original position, the motion would never result in a change in position. since velocity is defined as the rate at which the position changes, this motion results in zero velocity. if a person in motion wishes to maximize their velocity, then that person must make every effort to maximize the amount that they are displaced from their original position. every step must go into moving that person further from where he or she started. for certain, the person should never change directions and begin to return to the starting position.