Question

a magnet is at rest on the side of a refrigerator. the magnet experiences forces due to interactions with other objects, as modeled below. which of these interactions store potential energy? choose 2 answers: a the frictional interaction between the magnet and the refrigerator b the normal interaction between the magnet and the refrigerator c the gravitational interaction between the magnet and the earth d the magnetic interaction between the magnet and the refrigerator

Explanation:

• Option A: Frictional forces involve kinetic energy (heat) when there's motion, but static friction (here, magnet at rest) doesn't store potential energy. Friction is a dissipative force, not a potential - energy - storing interaction.
• Option B: Normal force is a contact force that balances other forces. It doesn't store potential energy as it's related to the compression/normal reaction at the surface, not a field - based or position - based energy - storing interaction like gravitational or magnetic.
• Option C: Gravitational interaction between the magnet and the Earth stores gravitational potential energy. The magnet has a height above the ground (or a position in the Earth's gravitational field), and the gravitational force can do work if the magnet moves vertically, so gravitational potential energy is stored.
• Option D: Magnetic interaction between the magnet and the refrigerator (which is likely magnetic - responsive) stores magnetic potential energy. The magnet and the refrigerator are in a magnetic field interaction, and work can be done by the magnetic force if the magnet moves, so magnetic potential energy is stored.

Answer:

C. the gravitational interaction between the magnet and the Earth
D. the magnetic interaction between the magnet and the refrigerator