What is the difference among moment, torque and couple?

AI Thread Summary
Moment and torque are defined as the product of force and distance (Fd), and they are essentially the same concept, though the point of reference is crucial for calculations. A couple consists of two equal and opposite forces that do not act along the same line, resulting in a consistent total torque regardless of the chosen point of reference. The torque from a couple can be calculated using the formula G=Fd_{perp}, where d_{perp} is the perpendicular distance between the forces' lines of action. Understanding these distinctions is vital for analyzing rotational dynamics in physics. The relationship among moment, torque, and couple highlights the importance of reference points in mechanical systems.
qpzm77gg
Messages
19
Reaction score
0
What is the difference among moment, torque and couple?

Moment = Fd
Torque = Fd
Couple mean two forces have same magnitude but opposite direction.

What is the relationship among them?
 
Physics news on Phys.org
Moment and torque mean exactly the same. You must always specify the point about which you are finding the moment (or torque) of a force. A given force will have different moments (or torques) depending on your choice of point.

A couple is a pair of equal and opposite forces not acting in the same straight line. What's special about a couple is that the total torque of such forces is the same about whichever point we choose. It is given by
G=Fd_{perp} in which d_{perp} is the perpendicular separation of the lines of action of the two forces. This is easy to show.
 

Thread 'Derivation of Hamilton's Principle: Questions'

I have recently been really interested in the derivation of Hamiltons Principle. On my research I found that with the term ##m \cdot \frac{d}{dt} (\frac{dr}{dt} \cdot \delta r) = 0## (1) one may derivate ##\delta \int (T - V) dt = 0## (2). The derivation itself I understood quiet good, but what I don't understand is where the equation (1) came from, because in my research it was just given and not derived from anywhere. Does anybody know where (1) comes from or why from it the...
View full post »

Similar threads

A Trying to understand couple stress in continua
Replies
6
Views
731
Moment of inertia where mass and torque are at a different positions
2
Replies
69
Views
5K
I Effects of External Torques on the Angular Momentum of Asymmetric Bodies
Replies
3
Views
2K
Moment of inertia (experiment)
2
Replies
67
Views
6K
Torque and Moment of Inertia of a Lever Arm
Replies
2
Views
3K
I Is it possible to create linear acceleration using nothing but different moments of inertia beteen a wheel and axle?
Replies
5
Views
1K
What Is the Instantaneous Center of Rotation and How Is It Chosen?
Replies
19
Views
4K
Reaction torque in a traction system
Replies
10
Views
2K
Is Newton's third law valid for rotation / Torque?
Replies
23
Views
4K
About torque and moment of inertia
Replies
30
Views
7K

Hot Threads

Recent Insights

Back
Top