Energy, Power, and Physics of Explosions Flashcards

Vocabulary flashcards covering core physics concepts of energy, power, energy density, fuel sources, and nuclear fission based on Chapter 1 lecture notes.

Energy

The ability to do work, which must be conserved and cannot be created or destroyed, only transformed into other forms such as heat, mechanical, or chemical energy.

Food Calorie (Cal)

A unit of energy used in biology and chemistry equal to $1000\,\text{cal}$ ($1\,\text{kilocalorie}$), defined as the energy required to raise the temperature of $1\,\text{gram}$ of water by $1\,\text{degree Celsius}$.

Joule (J)

The standard unit of energy used in physics, where $1\,\text{kWh} = 3.6\,\text{million J}$.

Kilowatt-hour (kWh)

A unit of energy used primarily in industries and households, equivalent to approximately $1000\,\text{Cal}$ or $3.6\,\text{million J}$.

Power

The rate at which energy is used over time, calculated as energy divided by time and measured in Joules per second ($\text{J/s}$) or Watts ($\text{W}$).

Trinitrotoluene (TNT)

An explosive chemical compound with an energy density of $0.65\,\text{Cal/g}$ ($2,723\,\text{J/g}$) that rapidly converts chemical energy to heat, producing expanding gases.

PETN

A modern high explosive with an energy density of $1\,\text{Cal/g}$ ($4200\,\text{J/g}$), containing $1.6$ times the energy per gram of TNT.

Energy Density of Gasoline

Contains $10\,\text{Cal/g}$ ($42,000\,\text{J/g}$), which yields $15$ times more energy per gram than TNT, though it requires oxygen from the air to burn or explode.

Energy Density of Batteries

Electrical energy storage that provides $340$ times less energy than an equivalent weight in gasoline, with auto batteries yielding $0.03\,\text{Cal/g}$ ($125\,\text{J/g}$).

Electrolysis

A chemical process that uses an electric current to split water into hydrogen gas ($\text{H}_2$) and oxygen gas ($\text{O}_2$).

Fuel Cell Stack

An assembly of individual membrane electrodes that combine hydrogen and oxygen to produce electricity and water.

Energy Density of Liquid Hydrogen

A chemical fuel containing $26\,\text{Cal/g}$ ($110,000\,\text{J/g}$), offering about $3$ times more energy per gram than gasoline, but $3$ times less energy per gallon.

Energy Density of Uranium-235

Nuclear fuel containing $20\,\text{million Cal/g}$ ($82\,\text{billion J/g}$), which is $30\,\text{million}$ times the energy density of TNT.

Nuclear Fission

A reaction in which heavy atomic nuclei split apart upon absorbing a neutron, releasing massive amounts of energy along with lighter radioactive elements.

Critical Mass

The minimum amount of fissionable material required to sustain nuclear chain reactions for large-scale energy release.

EV Battery Metals

Valuable elements found in electric vehicle battery packs, including lithium, nickel, cobalt, manganese, and aluminum.

Average Household Annual Energy Consumption

An average usage of approximately $12,000\,\text{kWh}$ per year, equivalent to burning about $360\,\text{gallons}$ of gasoline or $2,000,000\,\text{grams}$ of coal.