Forces and motion key terms

Newton's third law

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

action-reaction force pairs

Forces that two objects exert on each other that are equal in magnitude and opposite in direction.

Action-Reaction Forces

For every action, there is an equal and opposite reaction force acting on a different object.

Force Pair

A pair of forces that are equal in magnitude and opposite in direction, acting on two different objects.

Newton's third‑law pair

A pair of equal and opposite forces that act on two different objects, each force being the reaction to the other.

Balanced forces on one object

Forces acting on a single object that are equal in magnitude and opposite in direction, resulting in zero net force and no change in motion.

Newton's Second Law

The principle stating that the acceleration of an object is directly proportional to the resultant force acting on it and inversely proportional to its mass.

Resultant Force

The overall force acting on an object, calculated by vector addition of all individual forces.

acceleration

The rate of change of velocity of an object.

force

A push or pull acting on an object, measured in newtons (N).

acceleration

The rate of change of velocity of an object.

trolley

A wheeled vehicle used for transporting goods or materials, often used in experiments to study motion.

control variables

Factors that are kept constant during an experiment to ensure that the results are valid.

acceleration investigation

An experiment designed to study how different forces or masses affect the acceleration of an object.

acceleration

The rate of change of velocity of an object, measured in metres per second squared (m/s²).

resultant force

The overall force acting on an object, calculated by vector addition of all individual forces, which determines the object's acceleration.

light gate

A device used to measure the time taken for an object to pass through a specific point, often used in motion experiments.

ticker timer

An instrument that produces a series of dots on a moving tape to record the position of an object at regular time intervals.

acceleration

The rate of change of velocity of an object.

force

An interaction that causes an object to change its velocity, measured in newtons.

repeated measurements

Conducting the same experiment multiple times to ensure consistent results and improve reliability.

reliability

The degree to which an experiment yields consistent and repeatable results.

acceleration

The rate of change of velocity of an object.

uncertainty

The doubt that exists about the result of any measurement.

Newton's second law

The principle stating that the resultant force acting on an object is equal to the mass of the object multiplied by its acceleration.

acceleration

The rate of change of velocity of an object, measured in metres per second squared (m/s²).

acceleration

The rate of change of velocity of an object.

resultant force

The overall force acting on an object when all individual forces are combined.

stopping distance

The total distance a vehicle travels from the moment a driver perceives a need to stop until the vehicle comes to a complete stop, calculated as the sum of thinking distance and braking distance.

thinking distance

The distance a vehicle travels during the driver's reaction time, from the moment the driver recognizes the need to stop until they apply the brakes.