Simple Machines B/Compound Machines C

[olympiaddict]

general rule # 2 applies- printing out sources is not prohibited, and is in the spirit of the competition (they are reference materials, not an essay for example), therefore it should be legal.
This is actually very common practice.

[SWAnG]

No need to cite sources correct?

[caseyotis]

No need to cite sources correct?

I wouldn't think so. It's not plagiarism to use a source to help you.

[BSchiffer]

I know some people have mentioned using wood, but what types of materials do people suggest we use to build the levers (For division C)? One of my friends suggested using K'nex which are stiff and easy to manipulate, and I was wondering what other people think of this idea, since it is much easier for me (and cheaper) than getting wood.

[chinesesushi]

I know some people have mentioned using wood, but what types of materials do people suggest we use to build the levers (For division C)? One of my friends suggested using K'nex which are stiff and easy to manipulate, and I was wondering what other people think of this idea, since it is much easier for me (and cheaper) than getting wood.

K'nex. I used that K'nex to try to build my compound machine and it failed horrendously. Depending on the weights, the knex will probably pop out of the connectors. However, I suggest you experiment with knex. perhaps you'll come up with a better design than i did.

[Zoobanks]

At regionals we used a ruler and half a ruler for our levers. However, we are starting from scratch for states. We are going to use hardwood and a completely new design we drew up on the chalk board at regionals.

[Safeguards]

I know some people have mentioned using wood, but what types of materials do people suggest we use to build the levers (For division C)? One of my friends suggested using K'nex which are stiff and easy to manipulate, and I was wondering what other people think of this idea, since it is much easier for me (and cheaper) than getting wood.

I would think that buying such a massive amount of K'Nex would rack up some considerable expenses, but I don't have any experience with them so I wouldn't know but anyways, what's the concern with the pricing on wood?
For my lever I picked up less than $20 worth of wood and had more than enough to make my entire device.

[Flavorflav]

I think ours cost about $5, plus some scrap wood we had lying around.

[nxtscholar]

I have a question with regards to the practice compound machines test posted on this site. For 14b, it states that the way to find the effort needed for the first machine was (Force of resistance/Force of effort)/IMA x 100% = 60%. But the efficiency was for the entire machine. Therefore, if you were calculating for AMA, wouldn't it be the MA for the first machine times the MA of the second? In which case, doesn't force of resistance over force of effort as used in the answer key not account for this?

Also, it said the six simple machines were the pulley, incline, wedge, lever, screw, and wheel/axle. Isn't the gear one?

[chinesesushi]

The gear is not a simple machine. It is a derivation of the wheel and axle I think. Also, it explicitly states in the rules that those are the 6 simple machines to be tested.

As for the first question, the answer key is correct. AMA can be interpreted as the Fout of the entire machine over the Fin. I would believe that if you were to calculate the MA of the first machine and then use the output force as the input force of the 2nd machine, it would be the same result.