Gravitational and Magnetic Fields in Daily Life

Study Notes

Gravitational and Magnetic Fields

Forces caused by gravitational and magnetic fields are observable in daily life.
Engineers use knowledge of fields to generate forces in designs, such as roller coasters and headphones.

Force and Fields

A force is a push or a pull on an object, which can cause it to change its motion.
Forces happen in pairs when two objects interact with each other.
Forces can occur over great distances, such as the gravitational force between the Moon and the Earth.
Fields, including gravitational and magnetic fields, can exert a force at a distance.

Gravitational Fields

A gravitational field exists in and around every object with mass.
The strength of a gravitational field depends on the mass of the object.
A gravitational field generates a force only when a second object is placed in the field.
The gravitational force between two objects is always attractive, never repulsive.
The force depends on the distance between the objects and the mass of each object.

Magnets and their Fields

Every magnet has two poles, north and south, and it is impossible to have a magnet with only one pole.
Magnets can either attract or repel other magnetic objects, depending on the orientation of their poles.
Similar poles repel, and opposite poles attract.
A magnetic field around an object is the result of the object's material properties.
A material is magnetized when domains inside the material are aligned.
Permanent magnets have aligned domains, while temporary magnets have domains that can be aligned by a magnetic field.

Comparing Fields

Gravitational and magnetic fields both exert a force at a distance on an object.
The amount of force exerted by the field depends on the location of the object in the field.
Both fields can be mapped by their effects on certain objects.
Key differences between gravitational and magnetic fields include:
- Gravitational field strength depends on mass.
- Magnetic field strength depends on the magnetic properties of the material.
- Gravitational fields always attract, while magnetic fields can attract or repel.

Energy in a Field

An object in a field has potential energy due to its position in that field.
The gravitational potential energy of an object in a gravitational field depends on its mass and position.

Description

Explore how gravitational and magnetic fields influence objects in daily life, such as a ball thrown upward or a magnet holding paper on a refrigerator door. Learn how engineers leverage knowledge of fields to create forces in various designs like roller coasters and headphones.