Claim for balanced and unbalanced forces

Balanced force:

Consider a book kept on a table. Two forces act on the book. One is the gravitational pull that acts downwards and second is the upward normal force. These two forces act in opposite direction and balances each other due to which the book on the table is at equilibrium and maintains its motion.

Unbalanced force:

Consider a book sliding on the table from left to right. The force of gravity pulling downward and the force of the table pushing upwards on the book are of equal magnitude and opposite directions. These two forces balance each other. Yet there is no force present to balance the force of friction. As the book moves to the right, friction acts to the left to slow the book down. There is an unbalanced force; and as such, the book changes its state of motion. The book is not at equilibrium and subsequently accelerates. Unbalanced forces cause accelerations.

are their multiple choices ?

explanation:

at right angles to each other