Answer:
20 J
Explanation:
Given:
Weight of the book is, 
Height or displacement of the book is, 
The work done on the book to raise it to a height of 2 m on a shelf is against gravity. The gravitational force acting on the book is equal to its weight. Now, in order to raise it, an equal amount of force must be applied in the opposite direction.
So, the force applied by me should be equal to weight of the body and in the upward direction. The displacement is also in the upward direction.
Now, work done by the applied force is equal to the product of force applied and displacement of book in the direction of the applied force.
Therefore, work done is given as:

Therefore, the work done to raise a book to a height 2 m from the floor is 20 J.
C the correct but not sure?
I know
the answer do you want me to help you?
Hey there!
No, that would be a biologist. Biologists study biology, or life. They're focused on life cycles, cells, evolution, and so much more.
Physicists focus on physics. They learn about forces, motion, and the study of the universal forces like gravity, momentum, and speed. Just like mathematics, they study patterns and look for new discoveries to be found in the fields of science, physics, and even mathematics.
Hope this helps!