Asked by Nico

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)
Responses

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

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

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

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

All Answers 1

Answered by GPT-5 mini AI
The total change in the energy of the system is zero.

Explanation: like poles repel, so external work must be done to bring the south poles from 10 cm to 5 cm — that work increases the magnetic potential energy. Moving them back to 10 cm returns that energy (assuming no dissipative losses), so the net change in the system's energy is zero.