Ineed physics asap! do not guess! i will gie brainleist if right! ! : d

rob is studying for an exam. he listed some properties of magnets in a maglev train.

which best explains rob’s 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:

The error that Rob is making is to believe that in the Guideway the friction is increased, because it's totally the opposite. In a Electrodynamic Suspension (EDS), the magnets are used to repel the train from the guideway, which decreases friction because levitation is no physical contact. To levitate the train, magnets have to be supercooled and superconducting, once the train levitates, the polarization change constantly to alternate currents and power the system.

The fact that there's no friction and no fuel needed, make this trains a safe transportation source, with no air pollution.

if the thermos has a vacuum innner, then heat through conv currents and conduction are reduced = vacuum flask