Point moment in a beam

1. Apr 29, 2005

chandran

In a beam static problem i am trying to understand what a moment at a point means. A force at a point moves the point in the beam in the direction of the force. What does a moment at a point do. Will it rotate the point about some axis? What is that axis. A book shows a beam with a moment at the end.
what does it mean?

2. Apr 30, 2005

haynewp

It is an applied rotation at a point. A moment can be reduced to a 2 force couple.

Imagine attaching your car steering wheel to the side of a beam. If you twist the steering wheel to the right, you have applied a moment on the beam at the point the steering wheel is attached. You push down with your right hand (force down) and push up with your left hand (force up), this is the 2 force couple. The axis of rotation is parallel to your arms.

The moment just doesn't affect the point, but possibly the whole beam. If the moment is applied at the end, just imagine attaching the steering wheel at the end of the beam and twisting it.

There are some online tutorials on statics, I suggest you go through several of them.