Unit 1–Forces Around Us Study Guide

A south pole of a magnet attracts the north pole of another magnet due to the fundamental magnetic principle that opposite poles attract. Therefore, the correct answer is 'north'.

A compass operates based on the Earth's magnetic field, which allows it to align with the planet's magnetic poles. The other fields listed (electric, gravitational, thermal) do not influence compass functionality.

The shock from touching a doorknob is caused by static electricity, which builds up on surfaces and discharges when you touch a conductive object like a doorknob. Current electricity flows continuously, while static electricity is a sudden discharge.

Metal objects, like an iron door knob, can easily conduct electricity and accumulate static charge, leading to a shock when touched. Other materials like wood, plastic, or cotton are less likely to cause static shocks.

Getting a stronger magnet is the best solution because it will securely hold the papers on the refrigerator door, preventing them from falling off. Other options may not provide the same level of stability.

Paper clips and iron filings are both made of materials that are magnetic, allowing them to be attracted to a magnet. The other options are incorrect as they do not describe the properties of these materials.

The correct choice highlights practical uses of magnets: a magnetic latch secures a cabinet door, and a magnet can hold notes on a refrigerator, demonstrating how magnets can solve everyday problems effectively.

The correct choice includes objects made of ferromagnetic materials like iron, which are attracted to magnets. An iron nail and a paperclip are common examples, while scissors may also contain metal parts that are magnetic.

Magnetic charges follow the principle that opposite charges attract. Therefore, positive charges attract negative charges, and north poles attract south poles, confirming that they must be opposite to attract.

Lightning is a natural example of static electricity, as it occurs when electrical charges build up in clouds and are discharged, creating a bright flash and thunder. The other options do not involve static electricity.