Forces and Matter (EdExcel)

Force

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

Contact Forces

Forces that require physical interaction, e.g., friction, tension, normal force.

Non-Contact Forces

Forces that act at a distance, e.g., gravity, magnetism, electrostatic force.

Matter

Anything that has mass and occupies space.

Mass

Amount of substance in an object.

Volume

Amount of space that an object occupies.

Density

Mass per unit volume (ρ=m/V​).

Gravity

A force that pulls matter towards Earth.

Elasticity

The ability of matter to stretch and return to its original shape, e.g., rubber bands.

Pressure

Force applied over an area.

Scalars

Quantities with only magnitude, e.g., mass, distance.

Vectors

Quantities with both magnitude and direction, e.g., force, velocity.

Distance

A scalar quantity representing the total path traveled.

Displacement

A vector quantity representing the straight-line distance from start to end.

Velocity

Displacement per unit time, representing speed in a direction.

Friction Force

A resistive force that opposes motion between two surfaces in contact.

Newton's First Law

An object remains at rest or moves with constant velocity unless acted upon by an external force.

Newton's Second Law

Force is equal to mass multiplied by acceleration (F = ma).

Newton's Third Law

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

Balanced Forces

Net Force = 0 N; an object remains at rest or moves at constant speed.

Unbalanced Forces

Net Force ≠ 0 N; the object moves in the direction of the resultant force.

Momentum

The product of mass and velocity (p = mass × velocity).

Law of Conservation of Momentum

Total momentum before collision equals total momentum after collision if no external forces act.