The south poles of two bar magnets are 10 cm from each other. The poles are brought to 5 cm apart and then moved back to their original positions. How does the energy of the system change? (1 point)

Question

Responses

The potential energy of the system first decreases and then increases.
The potential energy of the system first decreases and then increases.

Both the potential and kinetic energy of the system decrease.
Both the potential and kinetic energy of the system decrease.

The total change in the energy of the system is zero.
The total change in the energy of the system is zero.

The kinetic energy of the system decreases because some of it is transferred to thermal energy.

Answer 1

When the south poles of two bar magnets are brought closer together, they repel each other. As they move from 10 cm apart to 5 cm apart, the system's potential energy decreases because they are moving into a position of higher interaction energies due to the repulsive force.

After they are brought to 5 cm apart and then moved back to their original position (10 cm apart), the potential energy of the system increases again as they are being moved back to a state where the like poles are farther apart and the repulsive force is reduced.

Therefore, the correct response here is:

The potential energy of the system first decreases and then increases.