couple


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couple

1. Chiefly hunting or coursing
a. a pair of collars joined by a leash, used to attach hounds to one another
b. two hounds joined in this way
c. the unit of reckoning for hounds in a pack
2. Mechanics a pair of equal and opposite parallel forces that have a tendency to produce rotation with a torque or turning moment equal to the product of either force and the perpendicular distance between them
3. Physics
a. two dissimilar metals, alloys, or semiconductors in electrical contact, across which a voltage develops
b. two dissimilar metals or alloys in electrical contact that when immersed in an electrolyte act as the electrodes of an electrolytic cell

Couple

A system of two parallel forces of equal magnitude and opposite sense. Under a couple's action a rigid body tends only to rotate about a line normal to the couple's plane. This tendency reflects the vector properties of a couple.

The total force of a couple is zero. The total moment C of a couple is identical about any point. Accordingly, C is the moment of either force about a point on the other and is perpendicular to the couple's plane. See Resultant of forces, Statics

The moment of a couple about a directed line is the component of its total moment in the line's direction. Couples are equivalent whose total moments are equal.

Couple

 

a system of two forces P and P’ acting on a rigid body that are equal to each other in absolute value, are parallel, and are opposite in direction—that is, P’ = – P (see Figure 1). A couple has no resultant. In other words, its action on a body cannot be mechanically equivalent to the action of any single force; accordingly, a couple cannot be balanced by a single force.

The distance l between the lines of action of the two forces is called the arm of the couple. The effect of a couple’s action on a body is described by the couple’s moment, which is represented by a vector M equal in absolute value to the quantity Pl and perpendicular to the couple’s plane on the side where the rotation

Figure 1

caused by the couple appears to be counterclockwise in a right-handed coordinate system. A basic property of a couple is that the effect of its action on a given body is not changed if the couple is shifted anywhere in its plane or in a plane parallel to its plane. In addition, if the absolute value of the forces of the couple and the length of the arm are changed while the moment of the couple is kept fixed, the effect on the body is not changed. Thus the moment of a couple can be regarded as applied to any point of the body. If two couples have identical moments M and are applied to the same body, they are mechanically equivalent to each other. Any system of couples that are applied to a given body is mechanically equivalent to a single couple having a moment equal to the geometric sum of the moment vectors of the couples. If the geometric sum of the moment vectors of a system of couples is equal to zero, the system is balanced.

S. M. TARG [19–4–85–3]

couple

[′kəp·əl]
(chemistry)
Joining of two molecules.
(electricity)
To connect two circuits so signals are transferred from one to the other.
(electronics)
Two metals placed in contact, as in a thermocouple.
(engineering)
To connect with a coupling, such as of two belts or two pipes.
(mechanics)
A system of two parallel forces of equal magnitude and opposite sense.

couple

Two equal and opposite parallel forces, with different lines of action, tending to produce rotation of a body; their moment equals the product of the magnitude of one of the forces and the perpendicular distance between them.
References in classic literature ?
The climax of it is a furious prestissimo, at which the couples seize hands and begin a mad whirling.
Now what does this man do but fall back a couple of hundred yards and then come rushing at me as hard as he could tear, with his nail-keg bent down nearly to his horse's neck and his long spear pointed straight ahead.
There was a big steamboat lay- ing at the shore away up under the point, about three mile above the town -- been there a couple of hours, taking on freight.
I think there is nothing more pathetic than to see one of these poor old childless couples taking a menagerie of yelping little worthless dogs to their hearts; and then adding some cursing and squawking parrots and a jackass-voiced macaw; and next a couple of hundred screeching songbirds, and presently some fetid guinea pigs and rabbits, and a howling colony of cats.
Pity, that was; pity to put that kind of a strain on us, because there was bad blood between us from a couple of weeks back, and we was only friends in the way of business.
You and Miss Smith, and Miss Fairfax, will be three, and the two Miss Coxes five; and for five couple there will be plenty of room.
Many young couples of my acquaintance, who have had no other reason for concealing the fact beyond their own whim, have thus slipped off without saying a word to anybody, and returned full-blown housekeepers, with "at home" days of their own, and everything else like real married people,--for, as said an old lady to me, "one can never be sure of married people nowadays unless you have been at the wedding.
When he had wandered about for a couple of days he found it quite easily.
I hunted for food among the trees, finding nothing, and I also raided a couple of silent houses, but they had already been broken into and ransacked.
The longer they looked the more did this elderly couple feel interested in the unknown youth, to whom the wayside and the maple shade were as a secret chamber, with the rich gloom of damask curtains brooding over him.
It was Fanny's first ball, though without the preparation or splendour of many a young lady's first ball, being the thought only of the afternoon, built on the late acquisition of a violin player in the servants' hall, and the possibility of raising five couple with the help of Mrs.
Down he sank in a chair--ran his hands through his hair-- And chanted in mimsiest tones Words whose utter inanity proved his insanity, While he rattled a couple of bones.