all mechanics topics

Force

A push or pull causing a change in speed, direction, or shape

Balanced Force

Equal in size and opposite in direction, giving a net force of zero

Unbalanced Force

Causes a change in motion (acceleration, deceleration, or change in direction)

Net Force

The overall force acting on an object after all forces are combined

SI Unit (Force)

Newtons (N)

Mass

The amount of matter contained within an object, measured in kilograms (kg)

Weight

The force of gravity acting on an object's mass, measured in newtons (N)

Gravity

A force that attracts objects with mass toward each other

Normal Force

The support force exerted by a surface on an object, acting perpendicular (90°) to the surface

Friction

A force that opposes motion between two surfaces in contact

Air Resistance (Drag)

A frictional force that opposes motion when an object moves through air

Applied Force

A force exerted on an object by a person or another object

Thrust

A force that pushes an object forward, often produced by engines or explosions

Newton's First Law

An object remains at rest or moves at constant speed unless acted on by an unbalanced force

Inertia

The tendency of an object to resist changes in its motion; more mass means more inertia

Newton's Second Law

An object accelerates in the direction of an unbalanced force (Fnet = ma)

Newton's Third Law

For every action force, there is an equal and opposite reaction force

Delta (Δ)

Physics symbol representing final minus initial values

Distance

How far an object travels, measured in metres (m)

Time

How long motion takes, measured in seconds (s)

Speed

Distance divided by time, measured in metres per second (m s⁻¹)

Acceleration

Rate of change of speed in one direction (m s⁻²)

Deceleration

Acceleration that decreases speed, or negative acceleration

Distance-Time Graph

Graph where gradient represents speed and a flat line means rest

Speed-Time Graph

Graph where gradient is acceleration and area under it is distance

Energy

The ability to do work

SI Unit (Work & Energy)

Joule (J)

Gravitational Potential Energy (ΔEp)

Energy stored due to height above Earth

Gravitational Potential Energy (ΔEp) Formula

ΔEp = mgΔh

Kinetic Energy (Ek)

The energy of an object due to its motion

Kinetic Energy (Ek) Formula

Ek = ½mv²

Energy Transformation

When energy changes from one form to another

Law of Conservation of Energy

Energy cannot be created or destroyed, only transferred or transformed

Work

Energy transferred when a force moves an object in the direction of the force

Work Formula

W = Fd

Work Done

Equal to the change in energy

Power

The rate at which work is done

Power Formula

P = W/t

SI Unit (Power)

Watts (W)