P1 Conservation and Dissipation of Energy

Vocabulary flashcards covering energy stores, transfer pathways, governing equations, mnemonics, conservation concepts, and calculation techniques from the P1 Conservation and Dissipation of Energy unit.

Law of Conservation of Energy

The fundamental principle stating that energy cannot be created or destroyed; it can only be transferred usefully, stored, or dissipated.

System

An object or group of objects. When a system changes, the way energy is stored changes.

Closed System

A system isolated from outside influences where the total net energy remains constant.

Chemical Energy Store

Energy stored in chemical bonds, found in items such as batteries, food, fuel, and muscles.

Kinetic Energy Store ($E_k$)

Energy associated with moving objects as they speed up or slow down.

Gravitational Potential Energy Store ($E_p$)

Energy stored in objects raised within a gravitational field.

Elastic Potential Energy Store ($E_e$)

Energy stored in stretched or compressed objects.

Thermal Energy Store

The total kinetic and potential energy of particles in an object, which changes with temperature.

Magnetic Energy Store

Energy stored in attracting or repelling magnetic poles.

Electrostatic Energy Store

Energy stored in attracting or repelling electric charges.

Vibrational Energy Store

Energy stored in vibrating systems, such as changes in pendulum amplitude.

Nuclear Energy Store

Energy stored in atomic nuclei that is released via nuclear fission or fusion.

Mechanical Work Pathway

An energy transfer pathway where energy is transferred when a force moves an object through a distance.

Electrical Work Pathway

An energy transfer pathway where energy is transferred by an electric charge moving through a potential difference.

Heating Pathway

An energy transfer pathway where energy is transferred due to a temperature difference.

Radiation Pathway

An energy transfer pathway where energy is transferred by electromagnetic waves, such as visible light or infrared radiation.

Kinetic Energy Formula

$E_k = \frac{1}{2} m v^2$, where $E_k$ is in $\text{J}$, mass $m$ is in $\text{kg}$, and speed $v$ is in $\text{m/s}$. Mnemonic: "ENERGY HALVES MY VELOCITY TOO".

Gravitational Potential Energy Formula

$E_p = m g h$, where $E_p$ is in $\text{J}$, mass $m$ is in $\text{kg}$, gravitational field strength $g$ is in $\text{N/kg}$, and height $h$ is in $\text{m}$. Mnemonic: "ENERGY MAKES GULLS HIGH".

Elastic Potential Energy Formula

$E_e = \frac{1}{2} k e^2$, where $E_e$ is in $\text{J}$, spring constant $k$ is in $\text{N/m}$, and extension $e$ is in $\text{m}$.

Work Done Formula

$W = F d$, where $W$ is in $\text{J}$, force $F$ is in $\text{N}$, and distance $d$ is in $\text{m}$. Mnemonic: "WORK FOR DONUTS".

Power (Work) Formula

$P = \frac{W}{t}$, where $P$ is in $\text{W}$, work $W$ is in $\text{J}$, and time $t$ is in $\text{s}$. Mnemonic: "WORK PAYS TAXES" ($W = P t$).

Power (Energy) Formula

$P = \frac{E}{t}$, where $P$ is in $\text{W}$, energy $E$ is in $\text{J}$, and time $t$ is in $\text{s}$. Mnemonic: "EXPERIENCE THE POWER" ($E = P t$).

Efficiency Formula

$e = \frac{\text{Useful Output}}{\text{Total Input}}$, expressed as a decimal or percentage, with input and output measured in $\text{J}$ or $\text{W}$. Mnemonic: "USE TIME EFFICIENTLY" ($u = t e$).

Extension Formula

$\text{Extension } e = \text{Final Length} - \text{Start Length}$, measured in meters ($\text{m}$).

Maximum Velocity Formula (Descending Object)

$v = \sqrt{2 g h}$, derived from $m g h = \frac{1}{2} m v^2$ in an ideal system where masses cancel out.

Dissipation

The spreading out of energy into non-useful stores, typically as thermal energy lost to the surroundings.

Energy Balance

$\text{Total Energy Input} = \text{Useful Energy Output} + \text{Wasted Energy Output}$.

Power Balance

$\text{Total Power Input} = \text{Useful Power Output} + \text{Wasted Power Output}$.

Sankey Diagram

A visual energy flowchart where the width of each arrow is directly proportional to the amount of energy.

FIFA Calculation Method

A four-step exam calculation technique: Formula (write equation), Insert values (substitute numbers and convert units), Fine-tune (rearrange algebraically), and Answer (calculate final numerical value with correct SI unit).