Cgs unit of force

The most commonly used system apart from SI is the cgs system based on the =ntiinetre, gram and second as the only base units. The unit of force is the dyne, ind the unit of energy is the erg. In electromagnetism, SI is associated with an independent base quantity of current, whereas cgs is associated with current as a derived quantity. 

DYNE (dyu) A unit of force One dyne equals the force necessary to give ] gram mass an acceleration of 1 centimeter/(secotu1Xsecond). (Tire dyne is the unit of force in the CGS system.)... 

POISE (P). A unit of dynamic viscosity. The unit is expressed in dyne second per square centimeter The centipoise (cP) is more commonly used The formal definition of viscosity arises from the concept put forward by Newton that under conditions of parallel flow, the shearing stress is proportional to the velocity giadieut. If lire force acting on each of two planes of aiea A parallel to each oilier, moving parallel lo each other with a relative velocity V, and separated by a perpendicular distance X, be denoted by F. the shearing stress is F/A and the velocity gradient, which will be linear for a true liquid, is V/X. Thus, Ft A = q V/X, where the constant if is the viscosity coefficient or dynamic viscosity of the liquid. The poise is the CGS unit of dynamic viscosity. 

You might occasionally see the centimeter-gram-second (cgs) system units instead of the SI units. In the SI system, the unit of force is the newton, while in the cgs system, the unit of force is the dyne. Using this system, the unit of work is called the erg and is equal to a dyne-centimeter. Applying a force of 1 dyne over a displacement of 1 cm expends one erg of work. 

P) a cgs unit of resistance to fluid flow (viscosity). If a force of 1 dyne is needed to force two fluid layers with 1 cm3 area that are 1 cm apart past each other at a speed of 1 cm/s, the liquid has a viscosity of 1 poise,... 

Using the cgs system with the dyne as the unit of force and erg as the unit of work is impractical for many applications (too large or too small numbers to work with), so the mks system of units is preferred. Then the force is in newtons (1 N = 105 dyn), and the unit of work is the joule (1 J = 107 erg). A rate of doing work of 1 J/s is 1 W. A watt is also a measure of electrical power, being 1 A flowing with a potential of 1 V. 

Force will be given in dynes if r is in cm and m and are in cgs units of pole strength. The strength of a magnetic field at a point distance r from an isolated pole of strength... 

Two unit quantities of magnetism concentrated at points unit distance apart in a vacuum repeal each other with unit force. If the distance involved in 1 cm and the force 1 dyne, the quantity of magnetism at each point is one cgs unit of magnetism. Dimensions... 

Poundal paun-d l impound + -al (as in quintal)] (1879) n. An obsolete, but still occasionally seen, unit of force (the force required to accelerate a lib mass Ift/s ), analogous to the dyne in the cgs system, both created many years ago to perpetuate the illusion that Newton s law of momentum change needs no proportionahty constant. 

Conversion factors for different units of force and of force per unit area (pressure) are given in Appendix A.I. Note that always in the SI system, and usually in the cgs system, the term g is not used. 

The inhomogeneous organization of the atoms at the surface of a condensed phase causes the phenomenon known as surface tension, y.The surface tension is the reversible work needed to create a unit surface area in a substance. The idea of surface tension goes back to the concept that the surface of a Uquid has some kind of contractile skin. The surface tension is sometimes called the specific surface energy, the intrinsic surface energy, or the true surface energy. Surface tension has the cgs units of ergs/cm or SI units of J/ml However, since work can be expressed as force times distance, the units are sometimes expressed as dyn/cm or N/m. 

Surface tension is a property of the surface of a liquid that allows it to resist an external force caused by the cohesion of similar molecules. It is responsible for many behaviors of liquids. Surface tension has a unit of force per unit length. The Systeme International (SI) unit is the newton per meter (N/m) the commonly used centimeter-gram-second (cgs) unit is the dyne per centimeter (dyn/cm). 

A dyne (abbreviation dyn) is the unit of force in the cgs system of units, and is commonly used to express surface tensions. 1 N = 100,000 dyn. 

Coulomb s law. This relationship poses no particular difficulties as a qualitative statement the problem arises when we attempt to calculate something with it, since the proportionality constant depends on the choice of units. In the cgs system of units, the electrostatic unit of charge is defined to produce a force of 1 dyne when two such charges are separated by a distance of 1 cm. In the cgs system the proportionality factor in Coulomb s law is unity and is dimensionless. For charges under vacuum we write... 

The three fundamental units of the SI and of the cgs systems are length, mass, and time. It has been shown that force can be regarded as having the dimensions of MLT-2, and the dimensions of many other parameters may be worked out in terms of the basic MLT system. For example ... 

Viscosity is the force in dynes required to move a plane 1 cm in area at a distance of 1 cm from another plane 1 cm in area through a distance of 1 cm in 1 s. In the centimeter-gram-second (cgs) system, the unit of viscosity is the poise (P) or centipoise (1 cP = 0.01 P). Two other terms in common use are kinematic viscosity and fluidity. The kinematic viscosity is the viscosity in centipoise divided by the specific gravity, and the unit is the stoke (cm /s), although the centistoke (0.01 st = 1 cSt) is in more common use fluidity is simply the reciprocal of viscosity. 

Equation (1) defines the units of surface tension to be those of force per length or Nm 1 in SI or dynes cm"1 in the cgs system. We see presently that these are not the only units used for 7. 

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