Week 1: Energy and Power

A set of vocabulary flashcards defining fundamental concepts, unit systems, equations, and energy classifications from the Week 1 lecture.

Energy

The capacity to do work, which means exerting a force and causing something to move.

Conservation of Energy

The principle stating that energy can be converted from one form to another but cannot be created or destroyed.

Derived Unit

A secondary unit that can be presented as a combination of fundamental (primary) units.

United States Customary System (USCS)

An English engineering unit system that uses foot (ft) for length, poundmass (lbm) for mass, second (s) for time, and Rankine (R) for temperature.

Unit Conversion

A process used to change the numerical values and units of measured quantities from one to another without changing the physical measurement of the quantity.

Power

The rate of energy use or the amount of energy consumed or produced per unit time in an activity, denoted by the symbol $P$.

Watt (W)

The International System of Units (SI) unit of power, defined as one joule per second ($1\,\text{J/s}$).

Horsepower (hp)

A unit of power in the United States Customary System (USCS), approximately equal to $745.7\,\text{W}$.

Celsius Scale

A temperature scale commonly used by engineers that has a convenient zero temperature corresponding to the temperature at which water freezes.

Kelvin (K) Scale

An absolute temperature scale with zero corresponding to absolute zero ($0\,\text{K}$ or $-273.15\,^\circ\text{C}$), the temperature at which all molecular and atomic motion ceases.

Kinetic Energy (KE)

The energy possessed by a system or object by virtue of its motion, calculated using the formula $\text{KE} = \frac{1}{2}mv^2$.

Potential Energy (PE)

The energy possessed by a system or object as a result of its position in a force field, calculated using $\text{PE} = mgh$.

Elastic Potential Energy

Energy stored as a result of the deformation of an elastic object, calculated using $E_e = \frac{1}{2}kx^2$.

Chemical Potential Energy

Energy stored in the chemical bonds between atoms and molecules of a substance.

Work

The product of force and distance ($W = F \times d$) when a force acts upon a body causing it to move and overcome a resistance.

Macroscopic Energy

Forms of energy that a system possesses as a whole with respect to an outside reference frame, such as kinetic and potential energy.

Microscopic Energy

Forms of energy related to the molecular structure and molecular activity of a system, independent of outside reference frames.

Internal Energy (U)

The sum of all microscopic forms of energy within a thermodynamic system.

Heat (Q)

The form of energy transferred between two systems (or a system and its surroundings) by virtue of a temperature difference.

Adiabatic Process

A thermodynamic process during which no heat transfer occurs across the system boundary ($Q = 0$).

Electrical Energy

A form of energy fueled by the transfer of electrons between positive and negative points within a conductor.

Photovoltaic Cell

A solid-state semiconductor device, also called a solar cell, that directly converts light energy into electricity.

Nuclear Fission

The process of splitting an atomic nucleus into two nuclei with smaller masses, releasing significant energy.

Renewable Energy Sources

Sustainable sources of energy that are constantly replenished, such as solar, wind, hydroelectric, geothermal, biomass, and tidal energy.

Non-Renewable Energy Sources

Energy resources that exist in fixed amounts and are consumed much faster than they can naturally form, such as coal, oil, natural gas, and nuclear energy.