# Homework Help: Free body diagram on moment and torsion

1. Oct 29, 2012

### marvincwl

1. The problem statement, all variables and given/known data
It's not exactly a homework question, just want to see if i have the right concept in drawing free body diagrams

See attached Picture.
In case 1, the object is fastened on plane x-z and the rectangular block is fastened to the T-block in y-z plane.

Will the force be transferred to the block as it is in case 2?

2. Relevant equations
nil

3. The attempt at a solution

see attached picture. I think My1 would not be created?

Thanks alot. Help is much appreciated.

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2. Oct 30, 2012

### aralbrec

No (I assume the forces are not directly applied to the block in case 1). The forces that exist between the block and the rest of the frame occur at the fasteners and the type of forces depends on what type of forces the fastener can exert. So if you break the block and frame apart, you would model the forces on the block as the forces exerted by the fasteners. Whether some component of the those external forces transmit to the block can be found out from the static equations.

3. Oct 30, 2012

### marvincwl

If this is fastened in a random vibration machine and the fasteners used are socket head cap screws?

The fasteners will only create a compressive force at the threads and at the contact of the cap and the block? so the g-force from the vibration is not transferred??!