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.
Action and reaction are equal in magnitude and opposite direction by they don't balance each other because they don't occur on the same body. Action is involved on one body and reaction is involved on another body.
Hope you understood...
Answer:
copper and aluminum have the highest thermal conductivity while steel and bronze have the lowest. Heat conductivity is a very important property when deciding which metal to use for a specific application.
Explanation:
brainiest pls
Answer:
Yes
Explanation:
The farther something is from the center of mass of an object such as a planet, the lower the gravitational force between them
F = GMm/d²
That's wave 'diffraction'.