Low IMA Pulley Task

davecutting
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Re: Low IMA Pulley Task

Postby davecutting » December 30th, 2017, 2:18 pm

PM2017 wrote:
davecutting wrote:
PM2017 wrote:Where are people getting their weights? They seem ridiculously expensive.


Try your HS physics department.


Thanks for the advice, but unfortunately, that solution isn't available to us.
One of the physics teachers at our school hates SciOly, so she won't help us. The other one doesn't have any to lend us, especially not for the whole year.


Try this: https://www.amazon.com/Ajax-Scientific- ... eel+weight

Or this: https://www.amazon.com/American-Weigh-S ... eel+weight

I'd probably go with the second one since I can 3D print an adapter, but the first one has a nice hook on it for your string. I'd also suggest setting up some sort of linear rod with a recirculating linear ball bearing so that the weight stays where it should.
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Re: Low IMA Pulley Task

Postby VictoryChicken » January 7th, 2018, 7:05 pm

Unome wrote:
VictoryChicken wrote:
Unome wrote:Agreed, this would be much easier. An illustration, for those not familiar with pulleys:

low IMA pulley.png


Wow thanks for the illustration! Could you explain how you apply the effort in the example of the pulley system with the IMA of 0.50? Would the effort be pulled up?

No, it's pulled downward as usual (because it's better to let gravity do the work for you).



Got it. Thanks!

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Re: Low IMA Pulley Task

Postby Ash123 » January 8th, 2018, 9:33 pm

Unome wrote:
Tesel wrote:The easier thing would be a simple block and tackle type pulley (I think that's what it's called). One fixed pulley and one movable pulley give you an IMA of 0.5 so long as you pull down on the movable pulley.

Agreed, this would be much easier. An illustration, for those not familiar with pulleys:

low IMA pulley.png


Hey! Sorry, but I’m still struggling to understand the 0.5 IMA pulley. How does the effort pull down if the Circle represents the disk of the pulley? Also how would you connect that to the 7:1 pulley?

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Re: Low IMA Pulley Task

Postby Unome » January 9th, 2018, 5:09 am

Ash123 wrote:
Unome wrote:
Tesel wrote:The easier thing would be a simple block and tackle type pulley (I think that's what it's called). One fixed pulley and one movable pulley give you an IMA of 0.5 so long as you pull down on the movable pulley.

Agreed, this would be much easier. An illustration, for those not familiar with pulleys:

low IMA pulley.png


Hey! Sorry, but I’m still struggling to understand the 0.5 IMA pulley. How does the effort pull down if the Circle represents the disk of the pulley? Also how would you connect that to the 7:1 pulley?

The effort pulls down if you make it more than twice as heavy as the load. Otherwise, it doesn't pull anything - hence the 0.5 IMA.
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Re: Low IMA Pulley Task

Postby Ash123 » January 9th, 2018, 1:20 pm

Unome wrote:
Ash123 wrote:
Unome wrote:Agreed, this would be much easier. An illustration, for those not familiar with pulleys:

low IMA pulley.png


Hey! Sorry, but I’m still struggling to understand the 0.5 IMA pulley. How does the effort pull down if the Circle represents the disk of the pulley? Also how would you connect that to the 7:1 pulley?

The effort pulls down if you make it more than twice as heavy as the load. Otherwise, it doesn't pull anything - hence the 0.5 IMA.


But how does the effort cause the pulley to move if it is connected to the disk of one of the pulleys? If I understand the diagnosis correctly, a string weaves through two disk and holds a load on one end while being fixed on the other. So how could the effort pull anything if it is connected to the disk?

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Re: Low IMA Pulley Task

Postby Unome » January 9th, 2018, 1:27 pm

Ash123 wrote:
Unome wrote:
Ash123 wrote:
Hey! Sorry, but I’m still struggling to understand the 0.5 IMA pulley. How does the effort pull down if the Circle represents the disk of the pulley? Also how would you connect that to the 7:1 pulley?

The effort pulls down if you make it more than twice as heavy as the load. Otherwise, it doesn't pull anything - hence the 0.5 IMA.


But how does the effort cause the pulley to move if it is connected to the disk of one of the pulleys? If I understand the diagnosis correctly, a string weaves through two disk and holds a load on one end while being fixed on the other. So how could the effort pull anything if it is connected to the disk?

The effort is connected to the axis of the pulley via a string. If you look at a video or build it, you might understand it a little better.
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Re: Low IMA Pulley Task

Postby Ash123 » January 12th, 2018, 2:30 pm

Is there any way to connect the high and low ima pulleys? I’ve been trying to think of a method but I’ve got nothing right now.

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Re: Low IMA Pulley Task

Postby ScottMaurer19 » January 12th, 2018, 2:34 pm

Ash123 wrote:Is there any way to connect the high and low ima pulleys? I’ve been trying to think of a method but I’ve got nothing right now.

Yes but I'm also unwilling to share this one
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Re: Low IMA Pulley Task

Postby Ash123 » January 12th, 2018, 11:45 pm

Unome wrote:
Ash123 wrote:
Unome wrote:The effort pulls down if you make it more than twice as heavy as the load. Otherwise, it doesn't pull anything - hence the 0.5 IMA.


But how does the effort cause the pulley to move if it is connected to the disk of one of the pulleys? If I understand the diagnosis correctly, a string weaves through two disk and holds a load on one end while being fixed on the other. So how could the effort pull anything if it is connected to the disk?

The effort is connected to the axis of the pulley via a string. If you look at a video or build it, you might understand it a little better.


Ohhhh ok so I watched a few videos and i think I get it now.
So for a 2:1 pulley, the effort is on the fixed pulley and load is on the movable pulley, but for the 1:2 pulley it’s vice versa, correct?


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