Physics and Chemistry Revision: Forces, Motion, Energy, and Chemical Reactions

Comprehensive vocabulary flashcards covering Newton's laws of motion, types of contact and non-contact forces, energy forms, work equations, atomic configurations, halogen reactivity, and chemical word equations from class notes and revision worksheets.

Force

A push or pull exerted from one object onto another, measured in Newtons ($\text{N}$) using an instrument such as a newton meter.

Force Diagram

A graphical representation showing how external forces act upon an object, using directional arrows to indicate the magnitude and line of action of each force.

Balanced Forces

Equal and opposing forces acting on an object that cancel each other out, resulting in zero net acceleration and causing the object to remain stationary or move at constant speed.

Unbalanced Forces

Forces acting on an object that are not equal in opposite directions, producing a non-zero net force that causes the object to accelerate or change motion.

Newton's First Law of Motion

The law stating that an object at rest remains stationary and an object in motion continues at a constant speed in a straight line unless acted upon by an external net force.

Newton's Second Law of Motion

The principle stating that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass, defined by the formula $F = ma$.

Newton's Third Law of Motion

The law stating that whenever two objects interact, the forces they exert on each other are equal in magnitude and opposite in direction (action-reaction pairs).

Weight

A non-contact downward force caused by the gravitational pull of the Earth acting on an object's mass.

Friction

A resistive contact force that opposes motion between two surfaces sliding or attempting to slide across one another.

Drag

A resistive force opposing the motion of an object moving through a fluid medium such as air or water.

Upthrust (Buoyancy)

An upward contact force exerted by a fluid that opposes the weight of an immersed or floating object.

Support / Normal Reaction Force

The perpendicular contact force exerted by a solid surface supporting the weight of an object resting upon it.

Compression Force

A squeezing contact force directed inward on an object, reducing its volume or length.

Torsion Force

A twisting force applied to an object when torque is exerted about its longitudinal axis.

Contact vs. Non-Contact Forces

Contact forces require physical touch between interacting objects (e.g., upthrust, friction, push, support), whereas non-contact forces act across a distance without physical contact (e.g., gravitational, magnetic, electrostatic).

Work Done

The measure of energy transferred when an external force moves an object through a distance, calculated as $\text{Work done} = \text{Force} \times \text{distance}$ ($W = Fd$).

Kinetic Energy ($KE$)

The form of energy an object possesses due to its motion, calculated by the formula $KE = \frac{1}{2}mv^2$, where $m$ is mass and $v$ is velocity.

Gravitational Potential Energy ($PE$)

The stored energy an object possesses based on its vertical position in a gravitational field, calculated as $PE = mgh$, where $m$ is mass, $g$ is gravity, and $h$ is height.

Law of Conservation of Energy

The fundamental principle that energy is never created or destroyed, but only transformed or transferred from one form to another (e.g., turning on a switch transforms electrical energy to light and heat energy).

Electron Configuration

The arrangement of electrons distributed among energy shells around the nucleus of an atom (e.g., Magnesium has $2, 8, 2$ and Fluorine has $2, 7$).

Halogen Reactivity Trend

The periodic pattern in Group 7 non-metals (Fluorine, Chlorine, Bromine) where chemical reactivity depends on the distance from the outer electron shell to the central positive nucleus.

Flame Test

An analytical laboratory procedure used to identify specific metal ions based on the characteristic emission color produced when exposed to a flame.

Chemical Word Equation

A textual description of a chemical reaction stating the reactant substances on the left and the product substances on the right of an arrow indicating transformation.

Combustion of Magnesium

The oxidation reaction where magnesium ribbon burns in the presence of oxygen to produce a white powder: $\text{magnesium} + \text{oxygen} \rightarrow \text{magnesium oxide}$.

Cellular Respiration (Sugar Oxidation)

The biochemical reaction in living organisms where sugar reacts with inhaled oxygen: $\text{sugar} + \text{oxygen} \rightarrow \text{carbon dioxide} + \text{water}$.

Photosynthesis

The biochemical process in plants combining carbon dioxide and water using radiant solar energy to synthesize chemical energy: $\text{carbon dioxide} + \text{water} + \text{energy from the Sun} \rightarrow \text{sugar} + \text{oxygen}$.

Fermentation

The anaerobic biological conversion of sugar by microorganisms such as yeast: $\text{yeast} + \text{sugar} \rightarrow \text{alcohol} + \text{carbon dioxide}$.

Precipitation Reaction

A chemical reaction in which two aqueous solutions react to form an insoluble solid salt: $\text{copper nitrate} + \text{sodium carbonate} \rightarrow \text{solid copper carbonate} + \text{sodium nitrate}$.