Scorable Transfers

MaeleeB
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Scorable Transfers

Post by MaeleeB »

Hi! I was wondering does anyone know what it means in the instructions where it says: "For a transfer to count for points, both simple machines must use mechanical advantages to transfer energy. (Ex: A wheel and axle, just turning, does not count.)" That confuses me that we have to transfer energy. :D
kinghong1970
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Re: Scorable Transfers

Post by kinghong1970 »

wheel and axle IMA is basically radius of Large wheel over radius of Small wheel.

so please feel free to correct me if i'm wrong but my understanding is...

Wheel & Axle
big wheel has radius of 3 cm = diameter of 6 cm
circumference = 6π

small wheel radius 1.5 cm = diameter of 3 cm
circumference = 3π

IMA = (R of big wheel / R of small wheel) = 3/1.5 = 2

theoretically, a 10 gram weight unwinding CCW on big wheel should lift 20gram weight winding CW on small wheel...

sans friction and all the other real world goodness.

Class 1 Lever
Effort arm = 6 cm
Load arm = 3 cm

IMA = Effort Arm / Load Arm = 6/3 = 2

theoretically, a 10 gram effort should lift a 20 gram load...

again, sans friction and all other real world goodness...

so my big question is... if for wheel and axle a 10 gr weight lifts a 11 gr weight, does it satisfy the rules? since clearly there is IMA that is allowing for larger mass to be lifted?
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Re: Scorable Transfers

Post by juddweeks »

Wheel and axles are pretty straight-forward if you keep one thing in mind: The axle and the wheel are fixed so each revolution of the axle corresponds to one revolution of the wheel. In order for the machine to count energy must be transferred from the wheel to the axle or vice versa.
ravichittari
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Re: Scorable Transfers

Post by ravichittari »

So, if there is a "toy car" part of the device that pulls a load up 10cm.. can it be counted for wheel and axel? the axel of is 2mm and wheel is 10 mm
When the car moves the energy is transfered from wheel to axel..

Trying to figure out if I have to really build a wheel with axel with couple of wheels connected with some axel and then use it or use a car that comes with wheel and axel but use it in a way that it does meaningful work of moving an object 10cm up to be counted for points?

Looking forward to the answer
chalker
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Re: Scorable Transfers

Post by chalker »

ravichittari wrote:So, if there is a "toy car" part of the device that pulls a load up 10cm.. can it be counted for wheel and axel? the axel of is 2mm and wheel is 10 mm
When the car moves the energy is transfered from wheel to axel..

Trying to figure out if I have to really build a wheel with axel with couple of wheels connected with some axel and then use it or use a car that comes with wheel and axel but use it in a way that it does meaningful work of moving an object 10cm up to be counted for points?

Looking forward to the answer
As always, this isn't the place for official comments or statements - soinc.org is. The rule of thumb I go by with concern to a wheel and axle setup is to ask yourself if the same setup would work if the wheel were able to spin independently of the axle. If so, it most definitely is NOT using a wheel and axle as a simple machine.
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Re: Scorable Transfers

Post by Unome »

ravichittari wrote:So, if there is a "toy car" part of the device that pulls a load up 10cm.. can it be counted for wheel and axel? the axel of is 2mm and wheel is 10 mm
When the car moves the energy is transfered from wheel to axel..

Trying to figure out if I have to really build a wheel with axel with couple of wheels connected with some axel and then use it or use a car that comes with wheel and axel but use it in a way that it does meaningful work of moving an object 10cm up to be counted for points?

Looking forward to the answer
A good way to think about this is to imagine a wheel and axle as basically being a lever rotated in a circle around the fulcrum. The lengths of the two beams of the "lever" correspond to the radii of the wheel and axle.
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Re: Scorable Transfers

Post by kinghong1970 »

ravichittari wrote:So, if there is a "toy car" part of the device that pulls a load up 10cm.. can it be counted for wheel and axel? the axel of is 2mm and wheel is 10 mm
When the car moves the energy is transfered from wheel to axel..

Trying to figure out if I have to really build a wheel with axel with couple of wheels connected with some axel and then use it or use a car that comes with wheel and axel but use it in a way that it does meaningful work of moving an object 10cm up to be counted for points?

Looking forward to the answer
i do recall seeing in the rules that the above example, if applicable, will be counted either as a wheel and axle OR a ramp, not both.
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Re: Scorable Transfers

Post by SPP SciO »

kinghong1970 wrote:
ravichittari wrote:So, if there is a "toy car" part of the device that pulls a load up 10cm.. can it be counted for wheel and axel? the axel of is 2mm and wheel is 10 mm
When the car moves the energy is transfered from wheel to axel..

Trying to figure out if I have to really build a wheel with axel with couple of wheels connected with some axel and then use it or use a car that comes with wheel and axel but use it in a way that it does meaningful work of moving an object 10cm up to be counted for points?

Looking forward to the answer
i do recall seeing in the rules that the above example, if applicable, will be counted either as a wheel and axle OR a ramp, not both.
We looked at some toy cars and didn't go with them. As stated above, a rolling car pushing/pulling on something isn't likely to score wheel and axle points. Neither is it good for inclined plane transfers, since no rolling is permitted.

Look into some simple gears you can power with a falling mass; gears that spin a shaft are a good wheel and axle transfer. We've also seen success with having wedges release suspended masses - I imagine the wedge will be a more popular simple machine with this year's energy source rules.
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Re: Scorable Transfers

Post by goodcheer »

ravichittari wrote:So, if there is a "toy car" part of the device that pulls a load up 10cm.. can it be counted for wheel and axel? the axel of is 2mm and wheel is 10 mm
When the car moves the energy is transfered from wheel to axel..

Trying to figure out if I have to really build a wheel with axel with couple of wheels connected with some axel and then use it or use a car that comes with wheel and axel but use it in a way that it does meaningful work of moving an object 10cm up to be counted for points?

Looking forward to the answer
It seems you are not understanding the use of a wheel and axle as a simple machine. The wheel and axle work together so when you turn the wheel, the axle turns or when you turn the axle, the wheel turns. Just pulling a toy car to get the wheels rolling only serves to reduce friction in carrying a load, which is not the correct use of a wheel and axle simple machine as per the requirements. An example would be: wrap a string around an axle, pull the string, rotate the axle, which also rotates the wheel. Have another string wrap around the wheel so when the wheel turns, it lifts an object by the string up 10 cm. For this to work, the wheel and axle rotates freely in place, but does not move forward or backward on a plane like the wheels of a toy car. Hope this helps.
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Re: Scorable Transfers

Post by goodcheer »

MaeleeB wrote:Hi! I was wondering does anyone know what it means in the instructions where it says: "For a transfer to count for points, both simple machines must use mechanical advantages to transfer energy. (Ex: A wheel and axle, just turning, does not count.)" That confuses me that we have to transfer energy. :D
Don't be confused. Just keep in mind, energy is being transferred whenever a simple machine is used. When effort is exerted at one end of a first class lever, for example, the energy is used to lift a load at the other end. Then, the energy output from the lever becomes the energy input or effort that is exerted on the next simple machine. You can actually measure and/or calculate how much energy is transferred in each step. But, you don't have to, just good to know it is happening. Science is happening:)
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