What is the difference between Change in Velocity and Average Velocity?
Answers are suggested in the very terms used! Change in velocity is Change in Velocity. Average velocity is Average velocity! But since these simple terms are basics of mechanics, kinetics etc we have to know them precisely. When a train starts from rest (velocity=0) and starts gaining ‘speed’, it is accelerating. Means every moment its velocity is rising. After few minutes it may gain a final velocity which may last for long time and this is constant velocity. In engineering it is required to know the behaviour of bodies when they are moving at constant velocity or changing velocity on in view of power/energy considerations. So it is necessary to know the change of velocity and especially rate of change of Velocity. Some time average velocity also is used to get some aggregate values.