Yes, it appears that there's missing (or hidden) information.

I'm not hiding anything. At least not deliberately.

If the forces from the wiggly red arrows don't have tangential components, then they won't spin up the disk/cylinder around A.

I'm not party to any tangential forces involved. That is to say, the only knowledge I have of the forces acting is the bland, X-component/Y-component values returned from the integration.

My thinking on why the body will rotate clockwise around A as the force causes A to rotate anticlockwise around B, is simply the conservation of momentum.

That is: if we assume zero friction in the bearing at A (which we must), and an absence of viscosity in the medium (air, water, vacuum) surrounding the body (again, we must since we have no information), then the orientation of the mass of the body will tend to remain the same as the assembly rotates around B, simply because there is no force acting on it to cause it to change that orientation.

The net affect of the body maintaining its orientation with respect to the universe(B, and the rigidly attached "wall"), as the point A rotates anticlockwise around B, is that the mass of the body appears to (and actually does) rotate clockwise with respect to A.

If you aren't concerned about how fast it will get there, you don't need the masses and just need the component of the total force on the cylinder tangential to B (i.e. perpendicular to the A-B line, which will rotate about B). At equilibrium, that force will be zero and all the force will be parallel to the A-B axis (unless the force is strong enough to stretch or break things...).

Agreed. The purpose of the freebody diagram, (and the static link from B to the "wall"), is to isolate this part of the mechanism from the rest of the Universe and so allow you to simplify the overall problem to one that calculates everything with respect B.

At risk of messing it up because I'm doing geometry in my head

I concur with your trig.

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority". I knew I was on the right track :)
In the absence of evidence, opinion is indistinguishable from prejudice.
), is to isolate this part of the mechanism from the rest of the Universe and so allow you to simplify the overall problem to one that calculates everything with respect B.

In reply to Re^3: [OT] Forces. by BrowserUk
in thread [OT] Forces. by BrowserUk

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.