Question

a bar magnet and a second object are hung from metal rods. the diagram below shows what happens when both objects are released. which best describes the object on the right? an iron bar a steel bar a bar magnet with its north pole on the left a bar magnet with its south pole on the left

Explanation:

1. Analyze the interaction: The left object is a bar magnet (N - S). When released, the right object repels the left magnet.
2. Recall magnetic principles: Like poles repel, unlike poles attract. If the right object repels the left magnet (whose right end is S), the left end of the right object must be S (since S repels S? No, wait—wait, the left magnet's right pole is S. Wait, no: the left magnet is N (left) - S (right). The right object, when released, moves away from the left magnet. So the interaction is repulsion.
3. For repulsion, both must be magnets with like poles facing. The left magnet's right pole is S. So the right object's left pole must be S? No, wait—wait, the left magnet: left is N, right is S. The right object, when they are released, the right object's left side is facing the left magnet's right side (S). If they repel, the right object's left pole must be S (because S repels S? No, S and S repel, N and N repel. Wait, no: the left magnet's right pole is S. So the right object's left pole: if they repel, it must be S (since S and S repel). Wait, but the options: "a bar magnet with its south pole on the left"—let's check the options.

Wait, another approach: Iron and steel are magnetic materials, but they are attracted to magnets (not repelled). So the right object must be a magnet (since repulsion occurs, which only happens between two magnets with like poles). So eliminate iron bar and steel bar. Now, between the two magnet options:

• Option 3: "a bar magnet with its north pole on the left"—so left pole N, right pole S. Then the left magnet's right pole is S. N and S attract, so they would pull together, not repel.
• Option 4: "a bar magnet with its south pole on the left"—left pole S, right pole N. The left magnet's right pole is S. S and S repel (like poles), so they push apart, which matches the diagram (the right object moves away from the left magnet). So this is correct.

Answer:

D. a bar magnet with its south pole on the left (assuming the options are labeled as A: iron bar, B: steel bar, C: north pole left, D: south pole left)