forces acting on the book when it rests in your hands are: gravity, the equal and opposite force exerted by your hand on the book (in opposition to force of gravity). Also, air pressure, but its from all sides so it cancels itself out.
Presumably, your desk pushes up with the same force that the book pushes down. If that is the case, the net force is ZERO.
5N.
Friction.
The force of your pencil or pen against the desk that your paper is on if you're writing something down. The force of your paper against the desk. The force of your book against the desk. In each case, the desk exerts the identical but opposite force against the object lying on it. If that were not true, the objects would deform the desk, or the desk would form a bump where the objects are lying on it.
When a ball moving hits a ball that is at rest and a human pulling out a book from a desk.
Potential.
5N.
Friction.
The force of your pencil or pen against the desk that your paper is on if you're writing something down. The force of your paper against the desk. The force of your book against the desk. In each case, the desk exerts the identical but opposite force against the object lying on it. If that were not true, the objects would deform the desk, or the desk would form a bump where the objects are lying on it.
poo
When a ball moving hits a ball that is at rest and a human pulling out a book from a desk.
Potential.
No. There is no such thing as a single force that is balanced or unbalanced, and a desk is not a force anyway.
work would be done if the book fell from the top of the desk to the floor because there has been some force through which the book fell down and therefore the book got displaced from his initial position . hence the work is done in this situation because it has a force and a displacement which is essential for the work to be done.
The force of gravity causes a book to fall, but someone has to push it to the edge of the desk, or off the desk so that the force of gravity is greater than the normal force acting on the book.
A book sitting on a desk is at rest. It is in motion if the book falls to the floor from the desk.
Paul J. Clemmer has written: 'Science supervisor's and administrator's desk book' -- subject(s): Handbooks, manuals, Science, Study and teaching (Higher)
Potential energy