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Re: Simple Machines B/Compound Machines C

Posted: October 7th, 2014, 9:01 pm
by blindmewithscience
Hmm, so if speed will need to be emphasized this year, what are the best designs for being fast while still retaining a high level of accuracy?

Re: Simple Machines B/Compound Machines C

Posted: October 8th, 2014, 5:01 am
by JonB
blindmewithscience wrote:Hmm, so if speed will need to be emphasized this year, what are the best designs for being fast while still retaining a high level of accuracy?

Accuracy is more important this year, but I believe that there will be a greater separation in the times it will take teams to get the ratios. I do not think we are going to see much of an overall increase in the accuracy of the devices (but, I have been surprised before).

All of the devices are basically going to work the same way because of the class of levers we have to use in this event. The "devil is in the details" for this event. Figuring out ways to quickly and consistently get your measurements and then creating fast calculations is where a majority of the time preparing for this event should be spent.

Re: Simple Machines B/Compound Machines C

Posted: October 8th, 2014, 1:21 pm
by Unome
JonB wrote:
blindmewithscience wrote:Hmm, so if speed will need to be emphasized this year, what are the best designs for being fast while still retaining a high level of accuracy?

Accuracy is more important this year, but I believe that there will be a greater separation in the times it will take teams to get the ratios. I do not think we are going to see much of an overall increase in the accuracy of the devices (but, I have been surprised before).

All of the devices are basically going to work the same way because of the class of levers we have to use in this event. The "devil is in the details" for this event. Figuring out ways to quickly and consistently get your measurements and then creating fast calculations is where a majority of the time preparing for this event should be spent.
That is the most informative statement I have ever heard about this event :)

Re: Simple Machines B/Compound Machines C

Posted: October 9th, 2014, 7:00 pm
by raxu
Quick Question: How much do you usually need to get for top scores in states for Compound Machines? The maximum is 100, but the U.S. record is probably at most 99... 12 seconds and 1.25% error? I'm not doing that...

Re: Simple Machines B/Compound Machines C

Posted: October 9th, 2014, 7:05 pm
by raxu
Also, what is the intended way of putting the 1st class + 2nd class lever? I was thinking about "abandoning" the second class lever - connect it to the fructum and just use the 1st class one, because that sounds 10 times simpler in math. But is there like a nifty design with those 2 levers that can just do the ratio in 1 go?

Re: Simple Machines B/Compound Machines C

Posted: October 9th, 2014, 7:56 pm
by chinesesushi
raxu wrote:Quick Question: How much do you usually need to get for top scores in states for Compound Machines? The maximum is 100, but the U.S. record is probably at most 99... 12 seconds and 1.25% error? I'm not doing that...
The changed it this year, but last year it was essentially just finding the ratio between 2 of them, so and that took the best teams ~15-25 seconds with varying degrees of accuracy. Top team had accuracy of ~1.5% and a time around ~22 s.
raxu wrote:Also, what is the intended way of putting the 1st class + 2nd class lever? I was thinking about "abandoning" the second class lever - connect it to the fructum and just use the 1st class one, because that sounds 10 times simpler in math. But is there like a nifty design with those 2 levers that can just do the ratio in 1 go?
There is no "intended way," but they have to be connected in series to each other. So the output of the 1st class lever must be in the input of the 2nd class lever. Or vice-versa. Rule 3a: The device must be a class 1 lever connected directly in series to a class 2 lever, each with a single beam of length less than or equal to 40.0 cm. So you can't just "abandon" the second class lever, or else they would have just called the event Simple Machines and have it be the same as the Div. B event.

Re: Simple Machines B/Compound Machines C

Posted: October 10th, 2014, 4:33 am
by Unome
raxu wrote:Quick Question: How much do you usually need to get for top scores in states for Compound Machines? The maximum is 100, but the U.S. record is probably at most 99... 12 seconds and 1.25% error? I'm not doing that...
At Booth Invitational last year, we got ~95 and the top team got ~98 I think (Auburn JHS, 5th in that event at Nats). But you're Div C, so the scores will probably be closer to 96-ish. It depends on what state you're in.

Re: Simple Machines B/Compound Machines C

Posted: October 10th, 2014, 4:43 am
by JonB
raxu wrote: But is there like a nifty design with those 2 levers that can just do the ratio in 1 go?

The design of the levers will not be that much different from team to team. There will be some teams who will figure out how to determine the ratios in "1 go", but this is extremely difficult. Although the devices might be the similar, how the teams use the device will vary.

Re: Simple Machines B/Compound Machines C

Posted: October 10th, 2014, 6:08 am
by chalker
chinesesushi wrote: Rule 3a: The device must be a class 1 lever connected directly in series to a class 2 lever, each with a single beam of length less than or equal to 40.0 cm. So you can't just "abandon" the second class lever, or else they would have just called the event Simple Machines and have it be the same as the Div. B event.
Also note 5.d. that talks about making an honest attempt to utilize a compound lever....

Re: Simple Machines B/Compound Machines C

Posted: October 10th, 2014, 3:37 pm
by slytherin
So, i made a normal lever with the fulcrum in the middle, and now me and my dad can't really figure out how to find the ratio of two weights, help?