* Static Friction: This is the friction that prevents an object from moving when a force is applied. It's like the "sticking" force.
* Kinetic Friction: This is the friction that acts on an object once it's already moving. It's like the "dragging" force.
When an object starts moving, static friction is overcome. This means:
* It's not that friction disappears, it changes from static to kinetic. Kinetic friction is usually less than static friction, which is why it *feels* like the object suddenly moves more easily.
* Some situations might make the change seem more dramatic: For instance, a very smooth surface might have very low kinetic friction, making it seem like friction has vanished.
In a purely theoretical physics scenario, there are concepts like "superfluidity" where friction essentially vanishes at extremely low temperatures. However, this is not something we encounter in everyday life.
