Answer:
0.612 kilograms.
Step-by-step explanation:
To solve this problem, we need to use the definition of work as the product of force and displacement.
(a) The work done on the book is the force applied to it multiplied by the distance through which it is moved. In this case, the force applied to the book is its weight, which is 6 newtons. The displacement of the book is 2 meters, because it is moved from one shelf to another shelf that is 2 meters higher. Therefore, the work done on the book is 6 newtons * 2 meters = 12 joules.
(b) The next person to take the book from the shelf accidentally drops it. When an object is dropped, it accelerates due to the force of gravity, which is 9.8 m/s². Since the force of gravity is the same for all objects, we can use the acceleration of the book to calculate its mass. Specifically, we can use the formula F = ma, where F is the force acting on the object (in this case, the force of gravity), m is the mass of the object, and a is its acceleration.
In this case, the force acting on the book is its weight, which is 6 newtons. The acceleration of the book is 9.8 m/s². Therefore, we can solve for the mass of the book using the formula F = ma: 6 newtons = m * 9.8 m/s². This simplifies to m = 6 newtons / 9.8 m/s² = 0.612 kilograms.
In summary, the work done on the book when it is picked up and moved to a higher shelf is 12 joules, and the mass of the book is 0.612 kilograms.