Forces and Magnets：练习题

A student observes a magnet being used to sort trash at a recycling center. Which of the following metal objects would be picked up by the magnet?

A student is conducting an experiment using two identical magnets and three different objects: a steel nail, a plastic ruler, and a copper coin. The student places each object on a smooth surface and moves a magnet toward it. Which of the following observations is correct regarding the magnetic force acting on these objects?

Two identical magnets, M1 and M2, are placed on a smooth table. M1 is fixed in place. M2 is released from a distance \(d\) away. If the North pole of M1 faces the South pole of M2, which of the following best describes the motion and forces involved?

Which of the following materials is a non-magnetic material?

A student places a bar magnet on a smooth table and brings a second bar magnet close to it. If the first magnet moves away from the second magnet without them touching, what can be concluded about the poles that are facing each other and the type of force acting between them?

What will happen to the direction of the magnetic force if you bring the South pole of one bar magnet toward the South pole of another bar magnet?

If you rub a plastic comb against a woollen sweater, it can pick up small pieces of paper. What type of force is acting here?

Forces and Magnets
A student is given three metal bars: Bar A (iron), Bar B (aluminum), and Bar C (steel). If a strong permanent magnet is brought near each bar, which bar(s) will experience a magnetic force of attraction?

Forces and Magnets
(a) What are the names of the two poles found on every magnet?
(b) Describe what happens when you bring the North pole of one magnet close to the North pole of another magnet.
(c) A student has a pile of shavings containing iron, copper, and aluminum. How can they use a magnet to separate one of these metals from the others? Which metal will be attracted?

Forces and Magnets
A student is testing the strength of three different magnets (A, B, and C). She measures the maximum distance (in cm) from which each magnet can attract a steel paperclip.

Magnet A: \(3\) cm
Magnet B: \(7\) cm
Magnet C: \(5\) cm

(a) Based on the data, which magnet is the strongest? Explain your reasoning.
(b) If the student uses a copper paperclip instead of a steel one, what will happen? Why?