Newton's Third Law - Vocabulary (Video Notes)

Vocabulary flashcards covering key terms related to Forces, Interactions, and Newton's Third Law as presented in the video notes.

Force

A push or pull on an object; an interaction between objects.

Interaction

The action between two objects where forces are exchanged; e.g., pushing against a wall.

Newton's Third Law of Motion

For every action, there is an equal and opposite reaction; when one object exerts a force on a second, the second exerts an equal and opposite force on the first.

Action force

The force exerted by object A on object B as part of the interaction.

Reaction force

The force exerted by object B on object A as part of the same interaction; equal in strength, opposite in direction.

Action-reaction pair

Two forces in a single interaction; always act on different objects and neither exists without the other; they are equal and opposite.

Equal and opposite forces

Forces in an action-reaction pair have the same magnitude but opposite directions.

External force

A force that acts on a system from outside the system; can cause acceleration.

Internal forces

Forces that act between parts within the same system; they cancel when considering the motion of the whole system.

System

The object or group of objects being analyzed; boundaries determine whether forces are internal or external.

Weight

Gravitational force acting on an object toward Earth.

Ground reaction force

The force exerted by a surface (the ground) on an object in contact, opposite to the object's weight.

Mass

A measure of the amount of matter in an object; determines how much it accelerates under a given force.

Acceleration

The rate of change of velocity; for a given force, acceleration decreases as mass increases (F = ma).

Friction

Resistive force between contacting surfaces that opposes motion.

Recoil force

The reaction force on the source of action, such as the backward thrust on a gun when it fires.

Action and reaction identification rule

In any interaction, the force exerted by one object on the other is the action force; the force exerted by the second object on the first is the reaction force.

Air resistance

A type of friction from air acting opposite to the motion of an object through air.