Engineering Units Flashcards
Secondary Dimensions
Combination of the primary dimensions
- Volume, Velocity
Primary Dimensions
Express in physical entity
- Length, Time, Temperature, Mass
Imperial System (english unit)
Centimeter, grams, seconds
Metric System
Meter, kilogram, seconds
A
Ampere: current
K
Kelvin: thermodynamic temperature
Mole
the amount of substance of a system
cd
Candela: luminous intensity
N
Newton: acceleration of kg mass
(m/s²)
J
Joule: work done due to a force of 1 N and displacement of1m in the direction of the force
W
Watt: work done per time
(J/s)
V
Volts: electrical potential between two point
(W/A)
Work (mechanical energy)
Force x Distance (Nm)(J)
Potential Energy
The energy required by position (height) mass and height also express in J (mgh)
Kinetic Energy
The energy acquired by motion (1/2mv²)
Heat (thermal energy)
One joule of energy that requires to raise the temperature of 1 kg of water by 1°C
Sensible Heat
The heat absorbed or transmitted by a substance during a change of temperature which is not accompanied by a change of state
Latent Heat
The energy that when added or removed from a body results in a change of state
*Vaporization
*Fusion
Enthalpy
Total energy content of a body kJ/kg
Specific Heat Capacity (Cp)
The amount of energy required to raise the temperature of a unit mass of material by a unit of temperature difference at constant pressure or volume
Thermal Conductivity (k)
The quantity of heat that will be conducted per unit time across a unit thickness of a material if a unit temperature gradient exist across the thickness
(W/m °C)
Thermal Diffusivity
The ratio of thermal conductivity to heat capacity and density (m²/s)
Heat Transfer Coefficient
The quantity of heat transferred across a unit surface area to a fluid when a unit temperature gradient exists between the surfaces and the fluid (m/(m² °C))
Dynamic Viscosity
Expressed as the resistance to a fluid to flow (Pa.s)
Porosity
= 1 - (bulk density/solid density)
Interparticle Porosity
= 1 - (bulk density/particle density)
