View Full Version : Re: Torque or moment about a joint

11-06-2007, 01:33 PM
A moment is a force couple -> Equal and opposite forces that are separated
by a given distance. Torque is the application of a force at a given
distance from a point on member. Torque will produce a moment but it can
produce other loads as well.

For example, say that you use a wrench to tighten a bolt. If you look at
the bolt, there will actually be two "loads" applied to it. One will be a
shear load in the direction you are pushing the wrench and the other will be
a moment that equals the (applied force)*(length) of the wrench handle. The
value of the moment is equivalent to a pure force couple across the head of
the bolt. You applied torque and it produced both a shear load and a moment
to the head of the bolt. If you used a socket in a drill to apply the
torque, you would only be applying the moment to the head of the bolt.


Donnie Curington
Senior Associate
Stress Engineering Services, Inc.
Houston, TX 77095

-----Original Message-----
From: Dale Cannavan [mailto:Dale.Cannavan@BRUNEL.AC.UK]
Sent: Tuesday, November 06, 2007 11:00 AM
Subject: Torque or moment about a joint

Dear Subscribers,

Can anyone explain / define the differences in the meaning of Torque and
Moment. It is often stated that they are synonymous; however, some
suggest they are different.

Thanks for your time,

Dale Cannavan

Ph.D. Candidate

Centre for Sports Medicine and Human Performance

Department of Sports Sciences

Brunel University

West London