- #1
Clockclocle
- 25
- 1
The instantaneous velocity at time a is defined as derivative of motion function f(t). It is not similar to average velocity in an interval of time. From the Newton law. If an object is at rest, we must exert a force to make it move, assume that there is no friction. Depend on the weight of object even though we exert enough force it won't move if we do not stay exert on it enough time then the object must have a small interval of time to change their status of motion. In reality we can't make things change "instantaneous", so I guess in that small interval of time when the object change their status of motion the velocity of the object is the same on all the interval and equal to f'(a)