Physics: Motion and Newton's Laws

Comprehensive vocabulary flashcards covering motion graphs, vectors, scalars, contact and non-contact forces, Newton's laws of motion, inertia, momentum, and collisions.

Scalar

A quantity that has magnitude only and generally cannot be negative.

Vector

A quantity that has both magnitude and direction; it can be negative because the sign indicates direction.

Speed Formula

The relationship used to calculate speed from distance and time: $\text{speed} = \frac{\text{distance}}{\text{time}}$.

Average Speed

The speed calculated when an object's speed changes during motion, given by $\text{average speed} = \frac{\text{total distance}}{\text{total time}}$.

Distance-Time Graph Gradient

Represents velocity; a steeper gradient indicates a faster speed, a horizontal line indicates the object is stationary, and a negative gradient indicates the object is returning to the starting point.

Velocity-Time Graph Gradient

Represents acceleration; a steeper gradient indicates greater acceleration, a horizontal line indicates constant speed, and a negative gradient indicates deceleration.

Area Under a Velocity-Time Graph

The area under the curve that represents the total distance travelled by the object.

Curved Line on a Motion Graph

On a distance-time graph, it shows changing velocity (acceleration or deceleration); on a velocity-time graph, it indicates that acceleration is changing.

Electrostatic Interaction

An interaction occurring between charged particles where they experience a force of attraction or repulsion.

Gravitational Attraction

An attractive force that occurs between particles with mass.

Contact Forces

Forces experienced in the opposite direction to contact, such as friction.

Friction

A contact force that opposes the motion of an object in contact with a fluid or surface, acting along the line of contact in the opposite direction to movement.

Free Body Force Diagrams

Diagrams that show the direction of forces acting on an object in a given situation.

Reaction Force

A force that always acts normal (perpendicular) to the line of contact, directed from the point of contact.

Weight

A gravitational force that always acts vertically downwards from an object's centre of mass.

Equilibrium (Scale Drawings)

A condition where force arrows are equal in length and opposite in direction, canceling each other out so the object travels at a constant velocity.

Newton's First Law

An object maintains a constant velocity unless acted upon by a resultant force; if a resultant force acts, the object will accelerate.

Acceleration

The rate of change in velocity over time, involving a change in the speed and/or direction of an object.

Terminal Velocity

The steady velocity achieved when driving force (thrust) is balanced by resistive forces (drag and friction), resulting in zero resultant force and zero acceleration.

Newton's Second Law

States that the acceleration or deceleration experienced depends on the direction and magnitude of the resultant force, expressed as $\text{Force} = \text{mass} \times \text{acceleration}$.

Inertia

The measure of how difficult it is to change the velocity of an object depending on its mass, defined as $\text{mass} = \frac{\text{force}}{\text{acceleration}}$.

Momentum

A physical quantity depending on an object's mass and velocity, calculated as $\text{momentum} = \text{mass} \times \text{velocity}$ with units of $\text{N}\,\text{s}$ or $\text{kg}\,\text{m}\,\text{s}^{-1}$.

Elastic Collision

A collision in which both total momentum and total kinetic energy are conserved before and after the interaction.