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?

The potential stays the same since the book is on the table. The kinetic energy stays the same since the book was only shoved.

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.

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 potential energy increases as the book is pushed across the table. The kinetic energy stays the same since the book was shoved.

1 answer

Let's analyze how the potential and kinetic energy change during the process of the book sliding across the table.

  1. Potential Energy: The potential energy of the book does not change throughout this process as long as it stays on the flat table. Potential energy is determined by the height of the object in a gravitational field. Since the book remains at the same height above the ground while resting on the table, its potential energy remains constant.

  2. Kinetic Energy: When the person shoves the book, it gains kinetic energy due to the force applied. The kinetic energy is given by the equation \( KE = \frac{1}{2} mv^2 \), where \( m \) is the mass of the book and \( v \) is its velocity. As the book slides across the table, it starts with a certain kinetic energy that increases upon being shoved. However, due to friction between the book and the table, the kinetic energy gradually decreases as the book slows down until it eventually comes to rest.

Putting this together:

  • Potential energy remains constant throughout the process because the height of the book does not change.
  • Kinetic energy increases as the book is powered forward by the shove and then decreases as friction slows it down.

The correct statement among those provided is:

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.