Screw Task

MyWorldRules
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Re: Screw Task

Postby MyWorldRules » November 24th, 2018, 1:43 pm

How do you guys plan on doing this task? I was planning on doing like what was suggested by "rolling" the screw. But I feel like that really isn't using gravity directly. Any ideas on how to do this using gravity?

nmurali2002
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Re: Screw Task

Postby nmurali2002 » November 24th, 2018, 2:13 pm

How do you guys plan on doing this task? I was planning on doing like what was suggested by "rolling" the screw. But I feel like that really isn't using gravity directly. Any ideas on how to do this using gravity?
We are thinking of tying a weight to a string and wrapping the string around the screw (which is in some sort of threaded block). Once you drop the weight, the screw (hopefully) rotates. But plenty can go wrong - I'm not sure if the string will have enough friction to actually exert a torque on the screw for example.

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PM2017
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Re: Screw Task

Postby PM2017 » November 24th, 2018, 2:45 pm

How do you guys plan on doing this task? I was planning on doing like what was suggested by "rolling" the screw. But I feel like that really isn't using gravity directly. Any ideas on how to do this using gravity?
We are thinking of tying a weight to a string and wrapping the string around the screw (which is in some sort of threaded block). Once you drop the weight, the screw (hopefully) rotates. But plenty can go wrong - I'm not sure if the string will have enough friction to actually exert a torque on the screw for example.
if you attach the other end of the string to the screw, the screw must turn; it won't just slip. (assuming you have enough gravitational force to overcome the friction.)
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honorstoise
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Re: Screw Task

Postby honorstoise » November 24th, 2018, 6:28 pm

If you attach an object to the screw does it count as a separate object or part of the screw

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Re: Screw Task

Postby cheese » November 24th, 2018, 8:17 pm

If you attach an object to the screw does it count as a separate object or part of the screw
I would consider it to be part of the screw.
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MyWorldRules
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Re: Screw Task

Postby MyWorldRules » November 25th, 2018, 8:20 am

I tried attaching a rope to the screw and then pulling the rope to rotate the screw. But I tested that and the screw doesn't rotate.

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Re: Screw Task

Postby killer225whale » November 25th, 2018, 10:13 am

I tried attaching a rope to the screw and then pulling the rope to rotate the screw. But I tested that and the screw doesn't rotate.
Sounds like you have too much friction in your system? Trying to rotate a screw in a threaded block (or a nut) probably has too much friction involved; I'd probably do it by using a partially-threaded machine bolt; the smooth part would be in some ball bearings (or just resting in two V mounts, with the string wrapped around the smooth part.

String drops, screw rotates, and have a wingnut or hex nut that moves along the threaded part of the bolt. If there's still too much friction, you can probably try oiling/greasing where the bolt contacts the mounts and the nut, or also wrapping tape or something around where the string wraps around the bolt to increase the diameter and the torque.

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Re: Screw Task

Postby Caesar » November 29th, 2018, 1:06 pm

When I was in div B I did this task by using a flame to break a string holding a mass. I think that design could be easily combined with the string task.
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Re: Screw Task

Postby TheSquaad » November 29th, 2018, 4:32 pm

If you attach an object to the screw does it count as a separate object or part of the screw
I would consider it to be part of the screw.
I wouldn’t. The event description never specified that the moved object has to be removable or unattached.

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Re: Screw Task

Postby C8H10N4O2! » December 4th, 2018, 1:47 pm

would i be allowed to have a screw task that is actually a pulley (but only 1 wheel), which is pulled by the force of gravity (a mass), and moves another mass or so 2 cm upwards? i just want to know if this technically works (i am converting rotational force into linear, would it just be a matter of wording it properly?)


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