Two magnets are held apart. Once released, the south pole of one magnet moves toward the north pole of another magnet until the magnets collide. How does the graph reflect the changes in energy that occur?

Question

Responses

Kinetic energy and velocity are at zero when the magnets are held apart, and both increase rapidly when they are released and move together. Energy stored in the magnetic field decreases.

The kinetic energy of the system is derived from the thermal energy created by increased velocity. Energy stored in the magnetic field does not change.

The velocity and kinetic energy of the system increase as the energy stored in the magnetic field increases.

Kinetic energy is at its peak when the magnets are first released, then it decreases steadily. Energy stored in the magnetic field becomes zero.

Answer 1

The best response to describe the changes in energy that occur when two magnets are held apart and then released to move toward each other is:

Kinetic energy and velocity are at zero when the magnets are held apart, and both increase rapidly when they are released and move together. Energy stored in the magnetic field decreases.

This is because, when the magnets are initially apart, they have potential energy due to the magnetic forces acting between them. Once they are released, this potential energy is converted into kinetic energy as they accelerate toward each other. As they come closer, the energy stored in the magnetic field decreases as it is converted into kinetic energy, leading to an increase in the velocity and kinetic energy of the magnets until they collide.