Question

rob is studying for an exam. he listed some properties of magnets in a maglev train. which best explains robs error? the current in the electromagnet of the guidance magnet does not change. the types of magnets are listed incorrectly in the table and should be switched. the unlike poles of the guideway and support magnets face each other. the repelling of the support magnet decreases friction.

Explanation:

To determine Rob's error, analyze each option:

• Option 1: Guidance magnets' current change is part of propulsion, not an error here.
• Option 2: Magnet types (guidance/guideway) mix - up isn't the main error.
• Option 3: Guideway - support magnet interaction: repulsion (like poles) is for levitation, but the error is about friction.
• Option 4: Maglev trains use magnetic repulsion (guideway and support magnets) to lift the train, reducing friction (not increasing). Rob said repelling increases friction, which is wrong. The repelling actually decreases friction.

Answer:

D. The repelling of the support magnet decreases friction.