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Forces and Motion - Magnetic Attraction and Repulsion

Grade 3IB

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

Magnets have two ends called poles: the North Pole (NN) and the South Pole (SS).

Magnetic Attraction is a 'pull' force that occurs when opposite poles are brought near each other (NN and SS).

Magnetic Repulsion is a 'push' force that occurs when similar (like) poles are brought near each other (NN and NN, or SS and SS).

Magnetism is a non-contact force, meaning magnets can exert a force through a space called a magnetic field (BB).

Only certain materials are magnetic; common examples include Iron (FeFe), Nickel (NiNi), and Cobalt (CoCo).

📐Formulae

North(N)+South(S)=Attraction (Pull)\text{North} (N) + \text{South} (S) = \text{Attraction (Pull)} Rose

North(N)+North(N)=Repulsion (Push)\text{North} (N) + \text{North} (N) = \text{Repulsion (Push)}

South(S)+South(S)=Repulsion (Push)\text{South} (S) + \text{South} (S) = \text{Repulsion (Push)}

💡Examples

Problem 1:

Sara holds two bar magnets. She points the North pole (NN) of the first magnet toward the North pole (NN) of the second magnet. What force will she feel?

Solution:

She will feel Magnetic Repulsion.

Explanation:

According to the laws of magnetism, like poles (NN and NN) push away from each other.

Problem 2:

A student places a magnet near a nail made of Iron (FeFe). What will happen?

Solution:

The nail will be attracted to the magnet.

Explanation:

Iron (FeFe) is a ferromagnetic material, meaning it is strongly attracted to the magnetic field produced by a magnet.

Problem 3:

If the distance (dd) between two attracting magnets is increased, what happens to the strength of the magnetic force (FF)?

Solution:

The magnetic force (FF) decreases.

Explanation:

Magnetic force is strongest when objects are close together and weakens as the distance (dd) between them increases.

Magnetic Attraction and Repulsion - Revision Notes & Key Formulas | IB Grade 3 Science