When you try to pull out a sheet from a note book, a slow motion raises the entire book, But a sudden motion detaches the sheet. See the video below for a demonstration.
The paper get detached because of the inertia of rest of the book.
What is inertia of rest?
The inherent property of a body at rest to resist any change in its state of rest is called inertia of rest.
OR in simple terms,
The incapability of a body to change its state of rest by itself is caled inertia of rest.