which is the force that slows a book sliding ona table
friction is the force. Friction is also what makes the heat when you rub your hands together really fast for a while, and without it, if you started running in an open field and then tried to stop, you would just keep going on forever until you collided with something
The force that slowed the book from sliding on a table is friction, friction is a type of force that causes things to slow down. In this the book slowed down because of friction.