Three metal bars, labeled 1, 2, and 3, are marked A and B on either end as shown

Question

Three metal bars, labeled 1, 2, and 3, are marked A and B on either end as shown.

The following observations are made by the student.

-end of 1B repels end 3A

-end 1A attracts 2B

-end 2B attracts 3B

a) Identify whether bar 1 is magnet, unmagnetized iron or aluminium. If you can't tell for sure, list the possiblities. Explain your reasoning.

b)Identify whether bar 2 is magnet, unmagnetized iron or aluminium. If you can;t tell for sure, list the possibilities. Explain your reasoning.

c) Would end 2A attract, repel or not interact with end 3A if two ends were brought together. If you can't tell for sure, what are the possibilities? Explain your reasoning.

Explanation / Answer

Alright, first off, lets label each bar magnet given the "rules" provided through the students experimentation. Keep in mind that opposites attract and like charges/polarities repel. 1. End of 1B repels end of 3A This means that 1B has the same polarity as 3A. Choose one charge(I will choose negative), and write those down. Since one end has a charge, the other end of the bar will have the opposite charge as well, so right down the opposite charge on the other ends of the bar: + ? - 1 2 3 - ? + Next, 1A attracts 2B, and 2B attracts 3B. This means that 2B must attract both 1A and 3B, which are both positive. This means that the metal could be either unmagnetized iron or a bar magnet with its negative pole at 2B. It could be unmagnetized because we are not 100% sure that 2A exhibits repulsion, only that 2B exhibits attraction to magnetic fields, which is exhbited by both iron and bar magnets. If you go strictly off the wording, 2 is actually a bar magnet, as it states that 2B attracts 3B, implying that 2 is exhibiting a magnetic force. For the last question, it doesn't really matter if the bar is a magnet or iron, because in both instances bar 2A will be attracted to 3A. In the magnet form, we determined that 2A has a positive charge, while 3A has a negative charge, which would attract. In an Iron bar form, 2 would be attracted due to 3A exhibiting a polarity which attracts the bar.

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