What is the difference between instantaneous and average when applied to velocity and acceleration?
Velocity is defined to be the change in the position of an object divided by the time interval over which this change occurs. For example, if you rode your bicycle 25 feet in 5 seconds your average velocity over the 5 second period would be v = 25 feet/5 seconds = 5 ft/sec. To find your instantaneous velocity [in other words your velocity at a particular moment in time] you would need to make the time interval very small. For example suppose you moved 0.25 feet in 0.05 seconds your instantaneous velocity would be v = 0.25 feet/0.05 sec = 5 ft /sec. Now looking at these two answers you may say, “but aren’t they the same?”, but they are not! In the first case the speed of the bicycle could have varied considerably over the 5.0 second time interval and so you don’t really know how fast the bicycle was going at any particular moment within the 5 second interval. On the other hand in the second case, where the time interval was 0.05 seconds, the speed of the bicycle could not have realistic
