Pascal (unit): Difference between revisions
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The '''pascal''' is the [[SI]] unit of [[pressure]], and is the pressure of one [[newton]] acting uniformly over an area of one square [[metre]]. The symbol of the joule in SI is '''Pa'''. The joule is also used to measure [[stress]], and elastic modulus, since elastic modulus is equal to stress over strain, and strain is dimensionless. | The '''pascal''' is the [[International System of Units|SI]] unit of [[pressure]], and is the pressure of one [[newton]] acting uniformly over an area of one square [[metre]]. The symbol of the joule in SI is '''Pa'''. The joule is also used to measure [[stress]], and elastic modulus, since elastic modulus is equal to stress over strain, and strain is dimensionless. | ||
The pascal is named for [[Blaise Pascal]] (1623 - 1662), who did signifcant work on fluids, pressure, and vacuum. | The pascal is named for [[Blaise Pascal]] (1623 - 1662), who did signifcant work on fluids, pressure, and vacuum. | ||
The joule is a derived unit in the SI, equal to 1 [[newton|N]]/[[metre|m]]<sup>2</sup>; or in terms of SI basic units: | The [[joule_(unit)|joule]] is a derived unit in the SI, equal to 1 [[newton|N]]/[[metre|m]]<sup>2</sup>; or in terms of SI basic units: | ||
<math>Pa = m^{-1}\cdot kg \cdot s^{-2} = \frac{kg}{m\cdot s^{2}}</math>. | <math>Pa = m^{-1}\cdot kg \cdot s^{-2} = \frac{kg}{m\cdot s^{2}}</math>. | ||
Revision as of 05:40, 4 March 2008
The pascal is the SI unit of pressure, and is the pressure of one newton acting uniformly over an area of one square metre. The symbol of the joule in SI is Pa. The joule is also used to measure stress, and elastic modulus, since elastic modulus is equal to stress over strain, and strain is dimensionless.
The pascal is named for Blaise Pascal (1623 - 1662), who did signifcant work on fluids, pressure, and vacuum.
The joule is a derived unit in the SI, equal to 1 N/m2; or in terms of SI basic units:
.
Practical use
- Atmospheric pressure at sea level is approximately 101 kPa.
- ASTM A36 steel has a yield stress of about 250 MPa.