Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie
Hi all! We have been experiencing an issue on site where threads have been missing the latest postings. The platform host Vanilla are working on this issue. A workaround that has been used by some is to navigate back from 1 to 10+ pages to re-sync the thread and this will then show the latest posts. Thanks, Mike.
Hi there,
There is an issue with role permissions that is being worked on at the moment.
If you are having trouble with access or permissions on regional forums please post here to get access: https://www.boards.ie/discussion/2058365403/you-do-not-have-permission-for-that#latest

Pulley problem

  • 23-07-2020 9:04am
    #1
    Lumen
    Registered Users, Registered Users 2 Posts: 31,141 ✭✭✭✭


    Engineers, I need your brains cos mine isn't working. This is a trivial problem for you, but I left school a long time ago.

    The requirement for the following design is to lift a heavy beam perpendicular to its long axis, i.e. without it tilting as it rises. The whole system is effectively acting as a wide pulley block.

    I think that, simplifying using g=10 and ignoring the horizontal component of forces, that

    f = 10,000N = sum(f2,f4,f6,f8,f10)
    t0 = t1 = ...t9 = 1,000N
    f2 = t1+t2 = 2,000N

    So each pulley deals with the same 1/5 of the load, and the tension in all sections of the rope is the same 1/10 of the load (for a point beam of zero length).

    If we consider a non-zero beam length, then as the beam gets longer the tensions increase, because the vertical component of the vector tension is a relatively smaller fraction of the load at the pulley fixture.

    I think that the free beam will rise parallel to the fixed beam. What do you think?

    IMG-20200723-090312.jpg


Comments

Advertisement