Simple Machines B/Compound Machines C

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Re: Simple Machines B/Compound Machines C

Postby UTF-8 U+6211 U+662F » March 19th, 2015, 2:56 pm

So... Apparently, there was a conflict, and now, I'm doing Simple Machines. What kinds of things should I do for simple machine concepts and terminology?
Just bringing this back up.

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Re: Simple Machines B/Compound Machines C

Postby Unome » March 19th, 2015, 3:52 pm

So... Apparently, there was a conflict, and now, I'm doing Simple Machines. What kinds of things should I do for simple machine concepts and terminology?
Just bringing this back up.
Just look at the Wikipedia page for every simple machine, and check some stuff on history.
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Re: Simple Machines B/Compound Machines C

Postby UTF-8 U+6211 U+662F » March 19th, 2015, 4:00 pm

Thanks!

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Re: Simple Machines B/Compound Machines C

Postby goodcheer » March 19th, 2015, 5:26 pm

Yes, a fixed counterweight would let the second class lever rest in equilibrium, which would hopefully allow for more accurate predictions.
But then it might not be considered a true 2nd class lever anymore... more like a hybrid 1st/2nd class lever....

If the fixed counterweight on the second class lever is not a good choice for balancing the beam, what would another option be? I'm guessing another option would be to adjust the fulcrum of the first class lever so it will hold up the second class lever in a level position?

Although, I would argue the fixed counterweight is used just for balancing the beam and only one side of the beam is used for measuring the ratios, making it in reality, practically speaking, a second class lever. But I don't know if we should chance it. It is a first class lever in appearance, but it is a second class lever in usage. Has anyone been able to use this set-up in competition?

Edit: Wouldn't the type of lever depend on how it is being used, not what it looks like? Is there any such thing as a "hybrid" lever? Anyone else want to "weigh" in on this? FAQ has been submitted.

I've been trying to think of an example of something that looks like one type of lever, but is actually another type. For example, a wheelbarrow is a typical second class lever, but it depends on how it is used. If you lift up on the handles and pivot on the wheel to lift the load in the middle, it is a second class lever. But if you push down on the handle and pivot on the legs of the wheelbarrow and lift the load upwards, it is a first class lever, with the fulcrum in the middle. The point being: a device can actually be made in such a way that it appears to be more than one type of lever, but how it is used determines what type of lever it is. It cannot be both types of levers at the same time in usage.

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Re: Simple Machines B/Compound Machines C

Postby UTF-8 U+6211 U+662F » March 21st, 2015, 1:17 pm

Yes, a fixed counterweight would let the second class lever rest in equilibrium, which would hopefully allow for more accurate predictions.
But then it might not be considered a true 2nd class lever anymore... more like a hybrid 1st/2nd class lever....

If the fixed counterweight on the second class lever is not a good choice for balancing the beam, what would another option be? I'm guessing another option would be to adjust the fulcrum of the first class lever so it will hold up the second class lever in a level position?

Although, I would argue the fixed counterweight is used just for balancing the beam and only one side of the beam is used for measuring the ratios, making it in reality, practically speaking, a second class lever. But I don't know if we should chance it. It is a first class lever in appearance, but it is a second class lever in usage. Has anyone been able to use this set-up in competition?

Edit: Wouldn't the type of lever depend on how it is being used, not what it looks like? Is there any such thing as a "hybrid" lever? Anyone else want to "weigh" in on this? FAQ has been submitted.

I've been trying to think of an example of something that looks like one type of lever, but is actually another type. For example, a wheelbarrow is a typical second class lever, but it depends on how it is used. If you lift up on the handles and pivot on the wheel to lift the load in the middle, it is a second class lever. But if you push down on the handle and pivot on the legs of the wheelbarrow and lift the load upwards, it is a first class lever, with the fulcrum in the middle. The point being: a device can actually be made in such a way that it appears to be more than one type of lever, but how it is used determines what type of lever it is. It cannot be both types of levers at the same time in usage.
Well, in a 2nd class lever, the load is in the middle of the effort, and the counterweight, in my opinion, doesn't count as the 'load,' so I'd say it is a 2nd class lever because it meets the requirements of a 2nd class lever.

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Re: Simple Machines B/Compound Machines C

Postby blindmewithscience » March 21st, 2015, 4:24 pm

Hi you guys, I'd like to check in with you all after my states competition last week.
So my event was run by someone that really wanted us to have a great competition--but IIRC, he was only put in the event that morning. We explained both portions of the event to him during the event. We had a 3 question test, all calculations, including one about dynamics. With the device testing, it took a while to make loops (which sadly, were not regulation).
Oh well, the guy that ran the event was really cool (graduate engineering student in the army), and we ended up placing first in the event.
I'd like to thank everyone here on this forum for all their help during this Science Olympiad season--it's been real fun. And maybe I'll be here again for Wind Power next year :)
I'll be back every now and then to help out with what I can on this forum. Thanks again to all of you, for being a great community!
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Re: Simple Machines B/Compound Machines C

Postby goodcheer » March 21st, 2015, 7:59 pm

Well, in a 2nd class lever, the load is in the middle of the effort, and the counterweight, in my opinion, doesn't count as the 'load,' so I'd say it is a 2nd class lever because it meets the requirements of a 2nd class lever.
Very well put. You should be moving up in the time dimension. Our team placed third in competition with this set-up.

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Re: Simple Machines B/Compound Machines C

Postby UTF-8 U+6211 U+662F » March 22nd, 2015, 7:13 am

Well, in a 2nd class lever, the load is in the middle of the effort, and the counterweight, in my opinion, doesn't count as the 'load,' so I'd say it is a 2nd class lever because it meets the requirements of a 2nd class lever.
Very well put. You should be moving up in the time dimension. Our team placed third in competition with this set-up.
I'm in B division, so... I'm not allowed to bring a 2nd class lever. :P :P

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Re: Simple Machines B/Compound Machines C

Postby goodcheer » March 25th, 2015, 10:36 am

Yes, a fixed counterweight would let the second class lever rest in equilibrium, which would hopefully allow for more accurate predictions.
Bernard: Here are the responses I just got from submitting two FAQs about this set-up. We actually placed at regionals with this set-up, so the ES didn't seem to have a problem with it.

ORIGINAL MESSAGE:

For the class 2 lever portion of the device, is it acceptable to build it out
of a class 1 lever where only one side of the class 1 lever is used for
testing, thus making it practically a class 2 lever?

No, that is not a class 2 lever by design.
=========================================================

ORIGINAL MESSAGE:

In order to balance the two levers, is it permissible to have a fixed counter
weight attached to the second class lever on the opposite side of the
fulcrum? This makes it a first class lever, but when used to determine the
ratios, it would be a second class lever.

No, because it isn't a true second class lever then. It would be with two 1st
class levers, which is not allowed.

=========================================================

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Re: Simple Machines B/Compound Machines C

Postby Royalreter » March 29th, 2015, 2:36 pm

Hey all,
I was wondering how you could solve "baby mobile" problems, like the one attached (sorry, easy problem and drew it up in like 2 minutes on paint). At regionals 2 weeks ago, we balanced the "lower" sections first and then just used the sum of all the weights under a branch on the "higher" sections of the mobile for it to balance. Not sure if this is the correct procedure, so any help would be appreciated.
Thanks!
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