Lever Tasks

[mnstrviola]

Okay, thanks for the advice. I think I'll not do it as well, because catapulting a ball into a basket on a lever was exactly what I was going to do

[mattravn]

Okay, thanks for the advice. I think I'll not do it as well, because catapulting a ball into a basket on a lever was exactly what I was going to do

Actually catapult might work as well, just add a big funnel so you can't miss

[losjackal]

IMA = Distance traveled by the Effort / Distance traveled by the Load

That's what I thought, but just discovered this clarification on soinc.org stating the opposite...?

HOW IS IMA DETERMINED?
IMA is determined by the output distance moved divided by the input distance moved.

But IMA is the force of output over force of input, and distance is inversely proportional, so the distance of input over distance of output.

To be perfectly clear, the question is asking about clarification of section 4.f. (compound levers for IMA > 5), but doesn't this calculation apply to 4.c. as well?
Where to have an IMA greater than 1, a lighter mass must travel a longer distance to lift a heavier mass a shorter distance.
The soinc.org answer would have the shorter distance in the numerator.

[chalker]

IMA = Distance traveled by the Effort / Distance traveled by the Load

That's what I thought, but just discovered this clarification on soinc.org stating the opposite...?

HOW IS IMA DETERMINED?
IMA is determined by the output distance moved divided by the input distance moved.

But IMA is the force of output over force of input, and distance is inversely proportional, so the distance of input over distance of output.

To be perfectly clear, the question is asking about clarification of section 4.f. (compound levers for IMA > 5), but doesn't this calculation apply to 4.c. as well?
Where to have an IMA greater than 1, a lighter mass must travel a longer distance to lift a heavier mass a shorter distance.
The soinc.org answer would have the shorter distance in the numerator.

Yeah, we've had some confusion over that. The clarification wasn't written thinking about all the possible devices IMA could apply to (i.e. block and tackle, compound levers, etc.. etc.). It was more to emphasize that with IMA you should be looking at distances moved, not forces.

[mattravn]

Now I think I might be confused. So task 4c says am IMA > 1 meaning lift a heavier mass with a lighter one. So for a first class lever you would have a longer arm / greater distance for the small weight lifting the shorter arm / lower distance for the heavy weight.... Yes?

By the same analogy the task 4f with ima of >5 would then need to have a large movement on the effort side to a small movement / larger force on the end with the load headed to the next task ?

Thanks. I think this is right but now not positive after reading some other posts.

[fleet130]

The clarification on soinc.org disagrees with my understanding of simple machines. Here is one website that explains it. Be sure to read the last section at the bottom of the page.

Mechanical Advantage (MA) is a general term that includes both IMA and AMA. Ideal Mechanical Advantage (IMA) and Actual Mechanical Advantage (AMA) refer to specific forms of MA.

Once again:

IMA is calculated using distances, with the distance moved by the input/effort in the numerator and the distance moved by the output/load/resistance in the denominator.

i.e. IMA = Distance(Effort) / Distance(Load)

AMA is calculated using forces, with the input/effort force in the denominator the the output/load/resistance force in the numerator.

i.e. AMA = Force(Load) / Force(Effort)

Also:

Efficiency = AMA / IMA
or
Efficiency = Work(Out) / Work(In)

[mnstrviola]

In the rules sheet for task c it says:

"Use a lever with an IMA greater than 1 in a manner that requires an IMA greater than 1 to
cause the next action (e.g., lift a heavier mass with a lighter mass)."

The rule clarification states that:

"IMA is determined by the output distance moved divided by the input distance moved."


So let's pretend we have a lever who's effort arm is twice as long as the load arm. The effort is therefore twice as light as the load.
Based on the rules sheet, this lever would have an IMA of 2.
Based on the rule clarification, this lever would have an IMA of 1/2.


Am I right in saying that the clarification contradicts with the rules?

[mattravn]

In the rules sheet for task c it says:

"Use a lever with an IMA greater than 1 in a manner that requires an IMA greater than 1 to
cause the next action (e.g., lift a heavier mass with a lighter mass)."

The rule clarification states that:

"IMA is determined by the output distance moved divided by the input distance moved."


So let's pretend we have a lever who's effort arm is twice as long as the load arm. The effort is therefore twice as light as the load.
Based on the rules sheet, this lever would have an IMA of 2.
Based on the rule clarification, this lever would have an IMA of 1/2.


Am I right in saying that the clarification contradicts with the rules?

It seems to me that the official clarification is backwards as well.

[aristocraft]

So I am totally confused here.I have done hours of research into this and come up with a formula for calculating IMA that is totally opposite of what is stated on the scioly website. The website states output (or resistance) should be divided by input (or effort) . But many and all other sites state that effort should be divided by resistance. This makes sense because you would be working with an IMA that is greater than 1 for your advantage -the websites formula you would be working in negative numbers even though you have an advantage. Please could someone clarify this for me as I have spent 100's of hours on my mission possible and don't really want to redesign to fit an incorrect calculation. To me the website is explaining the formula for AMA not IMA which our Rules manual states and that is how I built.

[chalker]

So I am totally confused here.I have done hours of research into this and come up with a formula for calculating IMA that is totally opposite of what is stated on the scioly website. The website states output (or resistance) should be divided by input (or effort) . But many and all other sites state that effort should be divided by resistance. This makes sense because you would be working with an IMA that is greater than 1 for your advantage -the websites formula you would be working in negative numbers even though you have an advantage. Please could someone clarify this for me as I have spent 100's of hours on my mission possible and don't really want to redesign to fit an incorrect calculation. To me the website is explaining the formula for AMA not IMA which our Rules manual states and that is how I built.

Yes, we know there is some confusion over the wording on the clarification. Thus I'd like to solicit suggestions on how to better word the clarification so that it makes sense and applies to all the possible IMA calculations that might need to be done (i.e. 1st, 2nd, 3rd class levers, compound levers, pulleys)