I have a question about bending moments with using this diagram as a reference.

Question

I have a question about bending moments with using this diagram as a reference. Can you think of bending moments it terms of equal and opposite reactions similar to forces where if one side is a certain direction then the other side has to be the opposite direction but same magnitude? Where for example if a beam is attached to a wall by a cantilever that can support a moment and a load is being applied to the beam, the moment that counters the moment caused by the load is caused by the wall and a opposite direction moment is applied to the wall.

thanks in advance for any assistance

Explanation / Answer

Bending moment can be considered as a resisting torque. Suppose in case of the cantilever, the end were connected with a pin joint rather than fixed, such that it is free to rotate about it, there would be no net moment about the point. Only when the rotation of the beam about the pivot is "restrained" (such as when the end is "fixed"), a bending moment develops at that point. You have marked the directions of the arrows on the beam correctly. The direction of moment on the wall will be equal and opposite to that on the beam from the wall. Since, the moment is clockwise on the beam, the moment on the wall will be counter-clockwise. Hope this clarifies your understanding.

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.