Newtons first law states "an object at rest will stay at rest while an object in motion will remain in motion" im confused as to what you are asking for but heres an example.
a car traveling at a speed of 35mph coming up to a stop sign has to slow down to a stop it cant stop instantly thats the same for it accelerating.
Some devices are used while moving around from place to place ... like in the car, on a bicycle, running, or walking the dog. If not for batteries, those devices would need very long extension cords.