When you hold your hands at your sides, you may have noticed that the veins sometimes bulge--the height difference between your heart and your hands produces increased pressure in the veins. the same thing happens in the arteries. if the average arterial pressure at your heart is a typical 100 mmhg, what is the average arterial pressure in your hands when they are held at your side? assume your hands are 60 cm below your heart.

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.