Question

the images below show four pairs of magnets. the magnets in different pairs do not affect each other. all the magnets shown are made of the same material, but some of them are different sizes and shapes. think about the magnetic force between the magnets in each pair. select the pair with the magnetic force of greatest magnitude. pair 1: a circle magnet (n and s) and a square magnet (n and s) with a distance of 1.25 in between. pair 2: a square magnet (n and s) and a circle magnet (n and s) with a distance of 2.75 in between. pair 3: a large rectangle magnet (n and s) and a circle magnet (s and n) with a distance of 1.25 in between. pair 4: a large rectangle magnet (s and n) and a circle magnet (s and n) with a distance of 2.75 in between.

Explanation:

To determine the pair with the greatest magnetic force, we consider two factors: the distance between the magnets and the strength of the magnets (related to size, as they are same material). Magnetic force is stronger when distance is smaller and when magnets are stronger (larger size, as same material means more mass/volume of magnetic material).

• Pair 1: Distance = 1.25 in. Magnets: one circle, one square (smaller size than Pair 3's large rectangle).
• Pair 2: Distance = 2.75 in (larger distance, so weaker force than Pair 1 or 3).
• Pair 3: Distance = 1.25 in (same as Pair 1), but the first magnet is a large rectangle (larger size, so stronger magnetic field) and the second is a circle. The large magnet has more magnetic material, so stronger force than Pair 1.
• Pair 4: Distance = 2.75 in (large distance, weaker force) and magnets are a large rectangle and circle, but distance is large.

Magnetic force depends on distance (inverse relationship, roughly) and magnet strength (proportional to size for same material). Pair 3 has the smallest distance (1.25 in) and the largest magnet (strongest), so it has the greatest magnetic force.

Answer:

Pair 3