DSK wrote:

Nav wrote:

You know, I've had more intelligent conversations than this with 3
year old.


I'm not so sure. Maybe a 4 year old, but you seem to be a bit above the
3 year old level. Except when you have these tantrums.


Considering that you haven't a clue how to resolve forces on a
free-body diagram


Nav wrote:

... Since you
claim it, show us why my answer is not in the "right ballpark".


http://groups.google.com/groups?hl=e...oogle%2BSearch



Say:

For simplicity let's say the rig has mast without any stays.

Mast 20' vertical Boom 10' horizontal. Gooseneck 3' from base of mast
Vang attched to point 3' from goosneck. 200 lbs to be lifted.

What is the bending moment on the boom at the vang if the load is held
by the vang?
What is the shear stress on the boom the load is held by the vang?
What is the compression force of the boom at the vang attachment?

Is that mast perfectly vertical? Is the boom perfectly horizontal?


Now let me quickly solve for the topping lift case:

If a topping lift is used, the bending moment at the vang is 0.
If a topping lift is used, the shear stress is 0
If a topping lift is used, the boom compression is 200 x 10 /17 = 118

lbs.

??? The compression on the boom depends on the angle betweenthe topping
lift & the mast, thus you cannot solve the problem with the info given.
For the record, the compression on the boom would be the weight
multiplied by the cosine of the angle.

What is the maximum stress at the vang attachment point in each case?

That depends on how hard you're talking at it.

Yes, as I said, no answer from you but one from me.

Cheers