Torque vs. Couple — What's the Difference?
By Tayyaba Rehman — Updated on November 6, 2023
Torque is a measure of the force that can cause an object to rotate about an axis, while a couple is a pair of equal and opposite forces whose effect is to rotate an object without translating it.
Difference Between Torque and Couple
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Key Differences
Torque is a physical quantity representing the rotational effect of a force applied to a rotational system at a distance from the axis of rotation. It is calculated as the product of the force and the distance from the point of application to the axis of rotation, leading to a change in the rotational motion of an object.
A couple, on the other hand, consists of two parallel forces that are equal in magnitude but opposite in direction, separated by a distance. This pair of forces produces rotation without any translation, meaning the object will turn without moving in space. The effect of a couple is to create rotational motion similar to torque but without any net force on the object.
In terms of application, torque is the force that mechanics apply to turn bolts and nuts using wrenches. The effectiveness of torque is determined by both the magnitude of the force and the length of the wrench. Torque is also what engines produce to enable the rotation of wheels.
Whereas a couple is a more specific term, often used in physics and engineering to describe forces applied in a rotational system without reference to any external point or pivot. The moment of a couple is calculated simply as one of the forces multiplied by the distance separating them since the forces are equal and opposite.
Finally, torque can be seen in many everyday applications, such as when opening a bottle with a twist-off cap. The torque applied by your hand causes the cap to rotate and open. In contrast, a couple might be used in a theoretical context to describe forces in a free body diagram that result in pure rotation, such as the forces exerted by two children sitting at opposite ends of a seesaw.
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Comparison Chart
Definition
Rotational force around an axis.
Pair of forces causing rotation.
Resulting Motion
Can cause rotation and translation.
Causes pure rotation without translation.
Calculation
Force multiplied by lever arm.
Force multiplied by distance between forces.
Application
Used in machinery, engines.
Used in theoretical physics, engineering.
Representation
Vector quantity.
Pair of vectors with equal magnitude, opposite direction.
Compare with Definitions
Torque
Rotational force applied at a distance from an axis.
The motor's torque turns the shaft.
Couple
Two equal forces acting in opposite directions.
The steering wheel's turn is due to the couple applied by the hands.
Torque
A measure of the twisting force on an object.
Apply more torque to loosen that bolt.
Couple
A pair linked together.
The couple walked hand in hand in the park.
Torque
The product of force and the radius at which it is applied.
Engineers calculate torque for optimal gear design.
Couple
To join or combine for a specific purpose.
Couple the two cables to extend their length.
Torque
A force that produces or changes rotational motion.
The wrench provides enough torque to turn the nut.
Couple
Two people or things of the same sort considered together
A couple of girls were playing marbles
Torque
The tendency of a force to rotate an object.
High torque in a car provides better acceleration.
Couple
Two people who are married or otherwise closely associated romantically or sexually
In three weeks the couple fell in love and became engaged
A honeymoon couple
Torque
In physics and mechanics, torque is the rotational equivalent of linear force. It is also referred to as the moment, moment of force, rotational force or turning effect, depending on the field of study.
Couple
An indefinite small number
Clean the stains with a couple squirts dishwashing liquid
He hoped she'd be better in a couple of days
We got some eggs—would you like a couple?
Just a couple more questions
Torque
The measure of a force's tendency to produce torsion or rotation about an axis, equal to the product of the force vector and the radius vector from the axis of rotation to the point of application of the force; the moment of a force.
Couple
Link or combine (something) with something else
A sense of hope is coupled with a palpable sense of loss
Torque
A turning or twisting force.
Couple
Mate or have sexual intercourse
As middle-class youth grew more tolerant of sex, they started to couple more often
Torque
A collar, a necklace, or an armband made of a strip of twisted metal, worn by the ancient Celts and Germans.
Couple
Two items of the same kind; a pair.
Torque
To impart torque to.
Couple
Something that joins or connects two things together; a link.
Torque
A rotational or twisting effect of a force; a moment of force, defined for measurement purposes as an equivalent straight line force multiplied by the distance from the axis of rotation (SI unit newton metre or Nm; imperial unit [https://en.wikipedia.org/wiki/Pound-foot_(torque) pound-foot] or lb·ft, not to be confused with the foot pound-force, commonly "foot-pound", a unit of work or energy)
Couple
Two people united, as by betrothal or marriage.
Torque
A tightly braided necklace or collar, often made of metal, worn by various early European peoples.
Couple
Two people together.
Torque
To make something rotate about an axis by imparting torque to it.
Couple
(Informal) A few; several
A couple of days.
Torque
A collar or neck chain, usually twisted, especially as worn by ancient barbaric nations, as the Gauls, Germans, and Britons.
Couple
(Physics) A pair of forces of equal magnitude acting in parallel but opposite directions, capable of causing rotation but not translation.
Torque
That which tends to produce torsion; a couple of forces.
Couple
To link together; connect
Coupled her refusal with an explanation.
Torque
A turning or twisting; tendency to turn, or cause to turn, about an axis.
Couple
(Electricity) To link (two circuits or currents), as by magnetic induction.
Torque
A twisting force
Couple
(Archaic) To join together in marriage; marry.
Couple
To form pairs; join.
Couple
To unite sexually; have sexual intercourse.
Couple
To join chemically.
Couple
Two or few
"Every couple years the urge strikes, to ... haul off to a new site" (Garrison Keillor).
Couple
Two of the same kind connected or considered together.
A couple of police officers appeared at the door.
Couple
Two partners in a romantic or sexual relationship.
Couple
(informal) A small number.
Couple
One of the pairs of plates of two metals which compose a voltaic battery, called a voltaic couple or galvanic couple.
Couple
(physics) A turning effect created by forces that sum to zero in magnitude but produce a non-zero external torque.
Couple
(architecture) A couple-close.
Couple
That which joins or links two things together; a bond or tie; a coupler.
Couple
Two or (a) small number of.
Couple
Two or a few, a small number of.
A couple fewer people show up every week.
I'll be there in a couple minutes.
Couple
(transitive) To join (two things) together, or (one thing) to (another).
Now the conductor will couple the train cars.
I've coupled our system to theirs.
Couple
To join in wedlock; to marry.
Couple
(intransitive) To join in sexual intercourse; to copulate.
Couple
(transitive) To cause (two animals) to copulate, to bring (two animals) together for mating.
Couple
That which joins or links two things together; a bond or tie; a coupler.
It is in some sort with friends as it is with dogs in couples; they should be of the same size and humor.
I'll go in couples with her.
Couple
Two of the same kind connected or considered together; a pair; a brace.
Adding one to one we have the complex idea of a couple.
[Ziba] met him with a couple of asses saddled.
Couple
A male and female associated together; esp., a man and woman who are married or betrothed.
Such were our couple, man and wife.
Fair couple linked in happy, nuptial league.
Couple
See Couple-close.
Couple
One of the pairs of plates of two metals which compose a voltaic battery; - called a voltaic couple or galvanic couple.
Couple
Two rotations, movements, etc., which are equal in amount but opposite in direction, and acting along parallel lines or around parallel axes.
Couple
To link or tie, as one thing to another; to connect or fasten together; to join.
Huntsman, I charge thee, tender well my hounds, . . . And couple Clowder with the deep-mouthed brach.
Couple
To join in wedlock; to marry.
A parson who couples all our beggars.
Couple
To come together as male and female; to copulate.
Couple
A small indefinite number;
He's coming for a couple of days
Couple
A pair of people who live together;
A married couple from Chicago
Couple
A pair who associate with one another;
The engaged couple
An inseparable twosome
Couple
Two items of the same kind
Couple
Something joined by two equal and opposite forces that act along parallel lines
Couple
Bring two objects, ideas, or people together;
This fact is coupled to the other one
Matchmaker, can you match my daughter with a nice young man?
The student was paired with a partner for collaboration on the project
Couple
Link together;
Can we couple these proposals?
Couple
Form a pair or pairs;
The two old friends paired off
Couple
Make love;
Birds mate in the Spring
Couple
Two people together, often in a romantic relationship.
The couple celebrated their anniversary at the restaurant.
Couple
Something that joins two things together.
The plumber used a coupling to connect the pipes.
Common Curiosities
What units is torque measured in?
Newton-meters (Nm) or foot-pounds (ft-lb).
Can a couple exist with only one force?
No, a couple requires two equal and opposite forces.
Do couples create linear motion?
No, couples only produce rotational motion without translation.
What is a moment of a couple?
It's the product of one of the forces and the distance between them.
Is torque used in vehicle engines?
Yes, torque is a measure of an engine’s rotational force.
How do you increase torque?
Increase the force applied or the distance from the pivot point.
What affects the amount of torque produced?
Both the magnitude of the force and the distance from the axis.
Are couples common in structural engineering?
Yes, they're considered in design to prevent undesired translations.
Can we have negative torque?
Torque can be considered negative if it produces rotation in the opposite direction.
Does a couple have a moment arm?
The moment arm for a couple is the distance between the two forces.
Can torque be zero?
Yes, if no force is applied or if the force is applied at the rotation axis.
Can a couple’s forces have different lines of action?
Yes, but they must be parallel and maintain equal magnitude in opposite directions.
Is torque a vector quantity?
Yes, torque has both magnitude and direction.
Is the effect of a couple dependent on the point of application?
No, the rotational effect of a couple is independent of the point of application.
Does torque affect rotational speed?
Yes, greater torque usually means higher rotational speed up to a point.
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Tayyaba RehmanTayyaba Rehman is a distinguished writer, currently serving as a primary contributor to askdifference.com. As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.
