Simple Machines B/Compound Machines C

[eladrinwizard1]

How big are the masses going to be? Also, how big are the loops?

Im a 1st year at SImleMachines

[eladrinwizard1]

Sorry, i meant to say Simple Machines.

For the ratio part, i was wondering if i should balance the weights on top, make a hole through it and tie a string on, or use another method to find the ratios.

[eladrinwizard1]

Clarification: This is for Division B. We have an invitational next Saturday, so fast help would be appreciated.

[Unome]

Sorry, i meant to say Simple Machines.

For the ratio part, i was wondering if i should balance the weights on top, make a hole through it and tie a string on, or use another method to find the ratios.

How big are the masses going to be? Also, how big are the loops?

Im a 1st year at SImleMachines

All of these can be answered by rereading the rules. The masses have a maximum size (I think 15x15x20 cm). I don't think the loops have a specific maximum size, however they have to be larger than some specified amount (I can't remember, it's in the rules). Most likely, the best method for finding the ratios is to hang them with the loops.

[chinesesushi]

Has anyone built their machine for Division C yet? If so, does it work

[blindmewithscience]

Has anyone built their machine for Division C yet? If so, does it work

My team's nearly done with ours. Hopefully it'll work .
We took some wood blocks to create stands for two metersticks. The metersticks are the fulcrums, and we drilled holes through them and inserted a screw for a fulcrum. The two metersticks are attached with a screw, with some room for movement. Hopefully that's not too terribly unclear
Have you built yours yet?

[chinesesushi]

Has anyone built their machine for Division C yet? If so, does it work

My team's nearly done with ours. Hopefully it'll work .
We took some wood blocks to create stands for two metersticks. The metersticks are the fulcrums, and we drilled holes through them and inserted a screw for a fulcrum. The two metersticks are attached with a screw, with some room for movement. Hopefully that's not too terribly unclear
Have you built yours yet?

that should work. i have not, but i should get on that as i have an invitational in like a month XD

[joeyjoejoe]

Has anyone built their machine for Division C yet? If so, does it work

We had our first meeting on this yesterday and had hoped to be buying materials today but we are still working on the math. If we leave all fulcrums alone and only adjust the positions of the weight, it seems that no matter where we fix our fulcrums, a scenario exists that is either impossible to measure or not optimal (1cm from fulcrum for ex.)- especially with the 10:1 max ratio for nationals.

We figured that the event creators probably designed the event this way and that we would meet next week to brain storm once again.
That's our approach at least: brainstorm:build is roughly 5:1

[blindmewithscience]

Has anyone built their machine for Division C yet? If so, does it work

We had our first meeting on this yesterday and had hoped to be buying materials today but we are still working on the math. If we leave all fulcrums alone and only adjust the positions of the weight, it seems that no matter where we fix our fulcrums, a scenario exists that is either impossible to measure or not optimal (1cm from fulcrum for ex.)- especially with the 10:1 max ratio for nationals.

We figured that the event creators probably designed the event this way and that we would meet next week to brain storm once again.
That's our approach at least: brainstorm:build is roughly 5:1

Hm, wait a minute. You can make it so that with the maximum ratio, you can get a distance of at least 4cm for the 10x weight. I can post something on calculations/stuff if you want, or let you figure it out for yourselves

EDIT: Or, by changing where you have the fulcrums are, you can achieve a much higher distance for the 10x mass.

[joeyjoejoe]

Yep, 4cm, not one like I said above.
If the fulcrum of the class 1 lever is in the middle and mass m1 was placed at the extreme end of it, then m2=10*m1 would balance the structure if placed 4cm from the fulcrum of the class two lever. If m2=8*m1 (a pretty big difference!) then it would balance at 5 cm - a measly one cm difference! Factor in friction and the possibility of a sloppy build and you've got yourself a mess!

...and your suggestion was exactly what we were looking at. If we move the fulcrum of the 1st class lever to the right so that it is 30cm from the left and 10cm from the right of the ends, the difference between 8x and 10x is equally multiplied so that the structure would balance at 15cm and 12cm respectively.
This seemed better but it has a major flaw! I wont tell what it is though. Just throw some examples into the equations and remember: we have no way of knowing exactly how much the masses weigh and many will have trouble determining which mass is heaviest - especially when they are very close.