When you lift a book from the ground to your desk, what kind of work do you do, negative or positive? by lifting the book what do you change? does the book gain engery or lose engery? what kind of engery?

1. When you lift a book from the ground to your desk, what kind of work do you do, negative or positive?

 The work is the product of the vector by the force by the distance; so if the direction in which the force is applied to the object and its displacement has opposite sign or are opposite, the work is negative. So, when you lift a book from the ground to your desk, you are applying a force upwards and the book is upwards too, then, both are going in the same direction. Therefore, the work is positive.

 2. By lifting the book what do you change?

 By lifting the book from the ground to your desk, its height changes, therefore you change its gravitational potential energy, which is equal to the mass of the book by height by the acceleration of gravity.

 3. Does the book gain energy or lose energy? What kind of energy?

 The book gains energy. The kind of energy that the book gains is called: "Gravitational potential energy".