A book is at rest on a flat table. A person gives the book a shove and it slides across the table. The book eventually comes to rest again near the edge of the table. How does the potential and kinetic energy change during this process?
1. The potential energy increases as the book is pushed across the table. The kinetic energy stays the same since the book was shoved
2. The potential energy will stay the same as long as the book stays on the table. The kinetic energy increases when the book is shoved and then gradually decreases as it slides across the table and then comes to rest on the edge.
3. The potential and kinetic energy are the same while the book is sitting on the table. They both increase when the book is shoved and then decrease as the book comes to rest again.
4. The potential stays the same since the book is on the table. The kinetic energy stays the same since the book was only shoved
2. The potential energy will stay the same as long as the book stays on the table. The kinetic energy increases when the book is shoved and then gradually decreases as it slides across the table and then comes to rest on the edge.
The correct answer is option 2: The potential energy will stay the same as long as the book stays on the table. The kinetic energy increases when the book is shoved and then gradually decreases as it slides across the table and then comes to rest on the edge.
Explanation:
Potential energy refers to the stored energy an object has due to its position or condition. In this case, when the book is at rest on the flat table, it has potential energy due to gravity. As long as the book stays on the table, its potential energy remains constant.
When the person gives the book a shove, they do work on the book, transferring energy to it. This transfer of energy causes an increase in the book's kinetic energy. The book starts moving across the table, converting the initial potential energy into kinetic energy.
However, as the book slides across the table, it experiences friction with the table surface, air resistance, and other forces. These forces act in the opposite direction to the book's motion, gradually slowing it down. As the book loses speed, its kinetic energy decreases.
Eventually, when the book comes to rest near the edge of the table, it has lost all of its kinetic energy and has come to a stop. At this point, its potential energy (due to gravity) remains the same as long as it remains on the table.
The correct answer is 2. The potential energy will stay the same as long as the book stays on the table. The kinetic energy increases when the book is shoved and then gradually decreases as it slides across the table and then comes to rest on the edge.
To understand why this answer is correct, let's break it down.
At the beginning, when the book is at rest on the table, it has a certain potential energy due to its position above the ground. This potential energy is converted into kinetic energy when the person gives it a shove. As a result, the book starts moving and gains kinetic energy.
As the book slides across the table, it experiences friction with the surface, which opposes its motion. This friction converts the book's kinetic energy back into potential energy in the form of internal energy (heat) in the book and the table. The book gradually loses its kinetic energy as it slows down and comes to a stop near the edge of the table.
Therefore, during this process, the potential energy stays the same, as long as the book is still on the table. The kinetic energy increases when the book is shoved, reaches a maximum while the book is sliding, and then decreases until it reaches zero when the book comes to rest again.