Edexcel IGCSE Physics – Forces and Motion

Newton's First Law of Motion

An object at rest stays at rest and an object in motion stays in motion at a constant speed and in a straight line unless acted upon by an unbalanced force.

Newton's Second Law of Motion

The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass, expressed as $F = ma$.

Newton's Third Law of Motion

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

Force

An interaction that causes an object to change its velocity, which can be described by a push or a pull.

Friction

A force that opposes the motion of an object, occurring when two surfaces in contact move relative to each other.

Inertia

The resistance of any physical object to any change in its velocity, including changes to the object's speed or direction.

Acceleration

The rate of change of velocity of an object with respect to time.

Mass

A measure of the amount of matter in an object, typically measured in kilograms.

Weight

The force exerted by gravity on an object, calculated as the product of mass and gravitational acceleration, expressed as $W = mg$.

Resultant Force

The overall force acting on an object when all individual forces are combined, determined by vector addition.

Momentum

The product of an object's mass and its velocity, expressed as $p = mv$, where $p$ is momentum, $m$ is mass, and $v$ is velocity.

Conservation of Momentum

In a closed system, the total momentum before an event (like a collision) is equal to the total momentum after the event, provided no external forces act on it.