#### Answer

The instantaneous velocity is an object's velocity at one moment in time. An object's average velocity is related to an object's displacement between two moments in time $t_1$ and $t_2$.
The average velocity can vary over different time intervals if the velocity is not constant.

#### Work Step by Step

The instantaneous velocity is an object's velocity at one moment in time. An object's average velocity is related to an object's displacement between two moments in time $t_1$ and $t_2$.
If the velocity is constant, then the average velocity will be the same between any two moments in time. However, if an object's velocity is not constant, the average velocity can vary over different time intervals.