forces and magnets year 8

Comprehensive practice flashcards defining all key vocabulary terms, concepts, and principles covered in the Year 8 Forces and Magnets coursebooklet.

Force

A push or pull acting on an object due to its interaction with another object.

Contact Force

A type of force that results when two interacting objects are perceived to be physically contacting each other.

Non-contact Force

A type of force that results even when two interacting objects are not in physical contact with each other, yet are able to exert a push or pull despite their physical separation.

Friction Force

A contact force that opposes or prevents motion when two objects rub or move against each other.

Tension Force

A pulling force that is exerted on an object by a string, rope, or rod.

Normal Force

A support force exerted upon an object that is in contact with another fixed or stable object, acting at right angles to the surface.

Applied Force

A force that is applied directly to an object by another object or person.

Spring Force

A force exerted on an elastic material that causes it to compress or stretch, temporarily altering its shape.

Air Resistance

A frictional force that acts against the direction of movement of an object travelling through the air.

Upthrust

An upwards support force (also called buoyancy force) that acts on an object when it is immersed in a fluid such as a liquid or gas.

Gravitational Force

A non-contact attractive force that exists between all bodies with mass.

Magnetic Force

A non-contact force exerted by a magnet on magnetic objects, such as iron and steel, usually acting over a short distance.

Electrostatic Force

A non-contact force experienced by a charged particle when placed in an electric field.

Drag

Friction that occurs specifically when an object moves through a fluid, such as air or water.

Scalar Quantity

A physical quantity that has only magnitude (size) and no direction.

Vector Quantity

A physical quantity that possesses both a magnitude and a specific direction, commonly represented using arrows.

Newton

The standard unit of force ($\text{N}$), defined as the force that causes a $1\,\text{kg}$ mass to accelerate at a rate of $1\,\text{m/s}^2$ ($1\,\text{N} = 1\,\text{kg}\cdot\text{m/s}^2$).

Forcemeter

An instrument containing an internal spring used to measure the magnitude of a force in newtons; also referred to as a newtonmeter.

Systematic Error

A consistent measurement inaccuracy occurring across all readings by the same amount, such as when failing to 'zero' a forcemeter prior to use.

Free Body Diagram

A diagrammatic representation where an object is shown as a box or dot, and arrows drawn from the centre represent the relative size and direction of all acting forces.

Resultant Force

The overall or net force acting on an object when multiple individual forces are combined together.

Balanced Forces

Opposing forces acting on a body that are equal in magnitude and opposite in direction, resulting in a net force of zero and zero acceleration.

Unbalanced Forces

Forces acting on an object whose vector sum does not equal zero, producing an acceleration and altering the object's speed, direction, or position.

Newton's Law of Gravity

A scientific law stating that every object with mass attracts every other object with a force proportional to their masses and inversely proportional to the square of the distance between them ($F_g = \frac{G m_1 m_2}{r^2}$).

Einstein's Theory of Gravity

A scientific explanation demonstrating that gravity is not an attractive pull, but rather the result of mass curving or warping the fabric of space and time.

Magnet

An object capable of attracting magnetic materials and producing an external magnetic field.

Ferromagnetic Materials

Specific metals that are strongly attracted to magnets and can be magnetised, including iron, steel, nickel, and cobalt.

Magnetic Poles

The two opposing ends of a magnet (designated north and south) where the magnetic field is concentrated and strongest.

Attraction

The pulling force that brings two objects together, observed when opposite magnetic poles (north and south) are placed near each other.

Repulsion

The pushing force that forces two objects apart, observed when like magnetic poles (north and north, or south and south) face each other.

Magnetic Field

The region surrounding a magnet within which its magnetic force can be detected and exerted on magnetic objects.

Magnetic Field Lines

Imaginary continuous lines indicating the direction and strength of a magnetic field; they never cross, are closest where the field is strongest, and point from north to south.

Compass

A navigational device containing a freely suspended magnetised needle that aligns itself with the local magnetic field lines.

Temporary Magnet

A magnetically soft material (such as an iron nail or paperclip) that becomes magnetised only in the presence of an external magnetic field and rapidly loses its magnetism once removed.

Permanent Magnet

A magnet made of magnetically hard material that retains its magnetic properties and domain alignment over long periods without an external magnetic field.

Magnetic Domain

A microscopic region inside a ferromagnetic material where atomic magnetic moments are naturally aligned in parallel.

Magnetisation

The process of aligning the magnetic domains within a ferromagnetic material in the same direction, achieved by stroking with a permanent magnet or applying an electric current.

Demagnetisation

The disruption of aligned magnetic domains into random orientations, eliminating net magnetism through high heat, heavy impact, hammering, or alternating currents.

Earth's Magnetic Field

A planetary magnetic field generated by molten iron circulation in the outer core that shields Earth from solar wind and aligns compass needles toward geographic north.

Electromagnet

A temporary magnet constructed by winding a coil of insulated wire around a magnetic core (such as iron) that produces a magnetic field only when an electric current flows.

Core

The central piece of magnetic material, typically soft iron, placed inside an electromagnet coil to dramatically enhance the magnetic field strength.

Soft Iron

A grade of iron that is magnetically soft, meaning it can be easily and quickly magnetised when a field is applied, and easily demagnetised when the field is removed.

Electric Bell

A mechanical signalling device that uses an electromagnet to attract an iron armature and hammer against a gong, automatically breaking and remaking the circuit to create a continuous ringing sound.

Electric Motor

A machine containing electromagnets that converts electrical energy into kinetic (mechanical) energy.