Simple Machines B/Compound Machines C

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Re: Simple Machines B/Compound Machines C

Post by Unome » April 27th, 2015, 5:58 pm

plaid suit guy2 wrote:What you're saying sounds like it does this.
Ohh... I should have mentioned which parts were stationary... I intended for both the gears to remain stationary.
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Re: Simple Machines B/Compound Machines C

Post by plaid suit guy2 » April 27th, 2015, 6:07 pm

Okay, so if both gears are stationary, then the big circle will be the 1.5m radius of the eccentric (I have no idea where 1.65 came from). The little circle will be the 2m radius of the dot from the center of it's shaft. Even if the two circles are the same size, it will always do this unless they are coaxial.
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Re: Simple Machines B/Compound Machines C

Post by plaid suit guy2 » April 27th, 2015, 7:32 pm

Double posting, but you are right, it isn't an eccentric, but you are wrong about the radii. The radius of the swing must be added to the radius of the second wheel. Meaning the radius would be seen as 2.5m if the swing is .5m. Yielding .6*5π=9.42m

Okay now that that is done: I have two problems.
The first: The easiest question on the Colorado State Comp-comp test:
Ignore friction. This lever is in static equilibrium with a force Fp applied by the piston at a 30° angle θ to the bar, what is the force applied to the fulcrum Φ?
divCstate.png
divCstate.png (11.15 KiB) Viewed 2172 times
The second is more a div B level question. What is the load mass to maintain static equilibrium on the lever? (this is so much lower in quality, sorry)
Div.b lever.png
Div.b lever.png (7.91 KiB) Viewed 2172 times
blue and yellow plaid suit
Nationals 2012:
Sound of Music: 8th

Nationals 2013:
Remote Sensing: 1st
ELG: 1st
MagLev: 6th

State 2014:
Boomi: 1st (scored 1824)
Circuits: 1st
Compound: 3rd
Malgev: 1st
MP: 2nd

total gold: 18
total silver: 10
total bronze: 5
6th: 1
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Re: Simple Machines B/Compound Machines C

Post by UTF-8 U+6211 U+662F » April 28th, 2015, 12:42 pm

plaid suit guy2 wrote:Double posting, but you are right, it isn't an eccentric, but you are wrong about the radii. The radius of the swing must be added to the radius of the second wheel. Meaning the radius would be seen as 2.5m if the swing is .5m. Yielding .6*5π=9.42m

Okay now that that is done: I have two problems.
The first: The easiest question on the Colorado State Comp-comp test:
Ignore friction. This lever is in static equilibrium with a force Fp applied by the piston at a 30° angle θ to the bar, what is the force applied to the fulcrum Φ?
Pulley: [math]\text{IMA} = 4[/math]
[math]20N/4 = 5N[/math]
[math]5N * 15 = 75N[/math]
[math]90 - 30 = 60[/math]
[math]cos(60) * F_p = \frac{F_p}{2}[/math]
[math]\frac{F_p}{2} * 5 = \frac{5F_p}{2}[/math]
[math]F_\phi = 75N - \frac{5F_p}{2} \text{upwards}[/math]

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Re: Simple Machines B/Compound Machines C

Post by plaid suit guy2 » April 28th, 2015, 1:10 pm

This is incorrect, Fp can be found, for one thing.
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Nationals 2012:
Sound of Music: 8th

Nationals 2013:
Remote Sensing: 1st
ELG: 1st
MagLev: 6th

State 2014:
Boomi: 1st (scored 1824)
Circuits: 1st
Compound: 3rd
Malgev: 1st
MP: 2nd

total gold: 18
total silver: 10
total bronze: 5
6th: 1
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Re: Simple Machines B/Compound Machines C

Post by UTF-8 U+6211 U+662F » April 28th, 2015, 1:19 pm

plaid suit guy2 wrote:This is incorrect, Fp can be found, for one thing.
There are two variables though... (and only one equation).

Unless I'm making some stupid mistake (still a little tired after States)

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Re: Simple Machines B/Compound Machines C

Post by plaid suit guy2 » April 28th, 2015, 1:20 pm

There are three equations, each with only one variable
blue and yellow plaid suit
Nationals 2012:
Sound of Music: 8th

Nationals 2013:
Remote Sensing: 1st
ELG: 1st
MagLev: 6th

State 2014:
Boomi: 1st (scored 1824)
Circuits: 1st
Compound: 3rd
Malgev: 1st
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total gold: 18
total silver: 10
total bronze: 5
6th: 1
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Re: Simple Machines B/Compound Machines C

Post by UTF-8 U+6211 U+662F » April 28th, 2015, 1:38 pm

plaid suit guy2 wrote:There are three equations, each with only one variable
I just give up.

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Re: Simple Machines B/Compound Machines C

Post by plaid suit guy2 » April 28th, 2015, 1:42 pm

You sure?
The first problem is this
divcanswer.png
Try the second question.
blue and yellow plaid suit
Nationals 2012:
Sound of Music: 8th

Nationals 2013:
Remote Sensing: 1st
ELG: 1st
MagLev: 6th

State 2014:
Boomi: 1st (scored 1824)
Circuits: 1st
Compound: 3rd
Malgev: 1st
MP: 2nd

total gold: 18
total silver: 10
total bronze: 5
6th: 1
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Re: Simple Machines B/Compound Machines C

Post by UTF-8 U+6211 U+662F » April 28th, 2015, 2:00 pm

plaid suit guy2 wrote:You sure?
The first problem is this
divcanswer.png
Try the second question.
Now I get it. I forgot the part... :oops:
4 kg
except... shouldn't the weight of the lever arm increase as the arm goes further away from the fulcrum?
Last edited by UTF-8 U+6211 U+662F on April 28th, 2015, 4:56 pm, edited 1 time in total.

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