Simple Machines B/Compound Machines C

[davidkim2106]

Ok so I made a lever like the diagrams and pictures shown in the previous posts. However, when I attach the string, how am I supposed to attach the second mass to the class 2 lever? If the string is connecting and blocking the two levers together, then I don't know how I could attach a mass to it.

[slytherin]

Ok so I made a lever like the diagrams and pictures shown in the previous posts. However, when I attach the string, how am I supposed to attach the second mass to the class 2 lever? If the string is connecting and blocking the two levers together, then I don't know how I could attach a mass to it.

I think people have been adding hooks to the lever that they attach the masses to..

[davidkim2106]

Could you please elaborate on it? I saw something about hooks but I wasn't sure what they were talking about.

[GoldenKnight1]

I know this is all unofficial but I was wondering how you would score a team for the 50pts of the device if when their 4 minutes started everything fell apart and it is clear to all they can't fix it in 4 minutes. I don't feel they should be allowed to guess the ratios as that goes against using their device, but what about time. Must they take the full time or can they stop the clock after say 10 sec and at least get a good time score?

[chalker]

I know this is all unofficial but I was wondering how you would score a team for the 50pts of the device if when their 4 minutes started everything fell apart and it is clear to all they can't fix it in 4 minutes. I don't feel they should be allowed to guess the ratios as that goes against using their device, but what about time. Must they take the full time or can they stop the clock after say 10 sec and at least get a good time score?

Rule 5.d. covers this situation pretty well: teams with no ratio estimates or that don't make an 'honest attempt' to utilize a lever to obtain ratios get R1,R1,TS=0.

[davidkim2106]

Could someone please explain the hook thing? Im confused

[blindmewithscience]

Could someone please explain the hook thing? Im confused

Whoops, thought I reliped to you last night...
So each mass will be attached to a loop, as specified in the rules. But with some compound levers, it's difficult or impossible to actually hook them onto the lever. In order to solve this, some teams have created loops that are a part of their machine. (I'm not at school and can't show you an example at one, but I think we do have one and I can take a picture of it tomorrow). Teams then put the loops on the hooks (so they don't have to attach them directly onto the lever).


Oh, For the B-teamers here, my school's team is getting on average .5% (!) accuracy in 2-3minutes (could get better) for a score of 42.5-45.

[davidkim2106]

OH!!! So what kinds of hooks would they be? Pictures would be awesome. Also, our lever doesn't seem to work, we use the right equation, but when we hang them directly (and then connect the two levers together with a string), our ratios are always off for some reason.

Any ideas? Thanks guys

[bernard]

OH!!! So what kinds of hooks would they be? Pictures would be awesome. Also, our lever doesn't seem to work, we use the right equation, but when we hang them directly (and then connect the two levers together with a string), our ratios are always off for some reason.

Any ideas? Thanks guys

If your masses are as far from the fulcrum as possible while still maintaining static equilibrium, 0.1cm of error isn't as much and won't affect your ratios as much. The loops on the masses are described in the rules. The hooks/calipers you use are up to you.

[jayrey]

help finding ratios!!

So I'm new to the compound machines event. I made my second class lever, much like the pictures from the previous posts (one bar higher than the other, connected by a string).

I'm getting consistent results but I don't know how to find the ratios? Is there a mathematical way to do it or measurements that I need to make? I can't figure it out. Please help!!