<em>Velocity is vector quantity.So it needs direction in addition to speed.</em>
<em>Explanation:</em>
<em>The velocity of an object is the rate of change of its position with respect to a frame of reference, and is a function of time. Velocity is equivalent to a specification of its speed and direction of motion. </em>
endorphins - chemicals ur brain releases endurance - ability to last a long time training cardiovascular- using ur heart lungs blood vessels using oxygen - aerobic using muscle - muscular