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Agurus Server Help Squatter

Age:39 Gender: Joined: May 05 2004 Posts: 353 Location: SSCI Halo Offline
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Posted: Tue Nov 07, 2006 8:20 pm Post maybe stupid Post subject: Lets do physics :-) |
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Mmm I cant figure out this ridiculous problem, I hate doing variables only. Can someone take a crack at it for me, I would apreciate if you showed me the steps you did to get there
File b3low
 _________________ X-SSCI Halo CTF Administrator
"I used to do drugs. I still do, but I used to, too."
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Mine GO BOOM Hunch Hunch What What

Age:41 Gender: Joined: Aug 01 2002 Posts: 3615 Location: Las Vegas Offline
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Posted: Tue Nov 07, 2006 9:47 pm Post maybe stupid Post subject: |
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To help you along without giving answers right out, first list some equations you know that can be used in this example.
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Blocks Novice

Joined: Jul 13 2006 Posts: 95 Location: California Offline
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Posted: Tue Nov 07, 2006 10:06 pm Post maybe stupid Post subject: |
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I'll give you some hints with which to get started.
Draw a free-body diagram. Call the horizontal direction x and the vertical direction y. You'll have two y forces from the weights, a force on the line of action of the wire (separate this out into x and y components), and a reaction at point A (defined by Asubx and Asuby).
Write out the equations for equilibrium, which would be the sum of the x forces equals zero, the sum of the y forces equals zero, and the sum of the moments about point A equals zero. You'll be able to write an inequality relating Asubx and Asuby under which equilibrium holds.
Maybe I gave away too much. Oh well, as long as you promise to understand what you're doing. There might be a simpler way to do it too.
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Agurus Server Help Squatter

Age:39 Gender: Joined: May 05 2004 Posts: 353 Location: SSCI Halo Offline
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Posted: Tue Nov 07, 2006 10:11 pm Post maybe stupid Post subject: |
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Well here are a few I think we could use:
(SUM OF)F=MA
Fs(max) = Us*Fn
W=MG=-Fn
Net External Torque= I * angular acceleration
or
SUM OF Torques = SUM OF MASSES r^2*alpha
Xcm= (m1(change in X))+m2(change in x2)/ (m1+m2)
I think we are supposed to split it to X and Y components but then have no idea what to do with the torques.
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Cyan~Fire I'll count you!

Age:37 Gender: Joined: Jul 14 2003 Posts: 4608 Location: A Dream Offline
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Posted: Tue Nov 07, 2006 10:17 pm Post maybe stupid Post subject: |
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Pay attention to blocks, you need to use the three equilibrium equations. _________________ This help is informational only. No representation is made or warranty given as to its content. User assumes all risk of use. Cyan~Fire assumes no responsibility for any loss or delay resulting from such use.
Wise men STILL seek Him.
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Agurus Server Help Squatter

Age:39 Gender: Joined: May 05 2004 Posts: 353 Location: SSCI Halo Offline
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Posted: Tue Nov 07, 2006 10:18 pm Post maybe stupid Post subject: |
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O_o didn't see his post, hmmm
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CypherJF I gargle nitroglycerin

Gender: Joined: Aug 14 2003 Posts: 2582 Location: USA Offline
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Posted: Tue Nov 07, 2006 10:21 pm Post maybe stupid Post subject: |
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i dreaded physics... still not sure how i passed the classes? (C in the first semester and B in the following (which the material was a lot harder)). *shrug* _________________ Performance is often the art of cheating carefully. - James Gosling
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Mine GO BOOM Hunch Hunch What What

Age:41 Gender: Joined: Aug 01 2002 Posts: 3615 Location: Las Vegas Offline
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Posted: Tue Nov 07, 2006 10:29 pm Post maybe stupid Post subject: |
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CypherJF wrote: | i dreaded physics |
I loved physics. Is it wrong that I knew the equations and method for how to solve that problem still, even though it has been about three years since I last bothered to touch torque/static friction?
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Agurus Server Help Squatter

Age:39 Gender: Joined: May 05 2004 Posts: 353 Location: SSCI Halo Offline
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Posted: Tue Nov 07, 2006 10:35 pm Post maybe stupid Post subject: |
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So assist me mgb
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Mine GO BOOM Hunch Hunch What What

Age:41 Gender: Joined: Aug 01 2002 Posts: 3615 Location: Las Vegas Offline
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Posted: Tue Nov 07, 2006 10:37 pm Post maybe stupid Post subject: |
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Blocks wrote: | I'll give you some hints with which to get started.
Draw a free-body diagram. Call the horizontal direction x and the vertical direction y. You'll have two y forces from the weights, a force on the line of action of the wire (separate this out into x and y components), and a reaction at point A (defined by Asubx and Asuby).
Write out the equations for equilibrium, which would be the sum of the x forces equals zero, the sum of the y forces equals zero, and the sum of the moments about point A equals zero. You'll be able to write an inequality relating Asubx and Asuby under which equilibrium holds.
Maybe I gave away too much. Oh well, as long as you promise to understand what you're doing. There might be a simpler way to do it too. |
Agurus wrote: | O_o didn't see his post, hmmm |
Follow his directions and write out the equations.
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Agurus Server Help Squatter

Age:39 Gender: Joined: May 05 2004 Posts: 353 Location: SSCI Halo Offline
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Posted: Tue Nov 07, 2006 10:41 pm Post maybe stupid Post subject: |
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Posts: 3001
Gj mgb ;P
Yeah ok I will try that
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Mine GO BOOM Hunch Hunch What What

Age:41 Gender: Joined: Aug 01 2002 Posts: 3615 Location: Las Vegas Offline
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Posted: Tue Nov 07, 2006 11:46 pm Post maybe stupid Post subject: |
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Agurus wrote: | Posts: 3001
Gj mgb ;P |
Well, it is my forums, and I do try to visit daily. Even so, I'm still not number one by a long shot. If you still want further help, make an MS Paint image of your diagrams and equations you currently have setup. If something is wrong, we'll help point it out for you.
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Muskrat Server Help Squatter

Age:38 Joined: Aug 24 2004 Posts: 829 Location: Swamp Offline
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Posted: Wed Nov 08, 2006 1:45 am Post maybe stupid Post subject: Re: Lets do physics :-) |
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Agurus wrote: | I hate doing variables only. | If you actually want to retain an ability at physics or ever use this stuff, you should be doing variables only on every single problem until the last step. Starting with numbers and doing algebra(& mebe a little cal) will not give you a very good idea of what is really going on.
And yeah, free body diagrams help..... boy I'm glad I got my A and moved on from that class. But then again electricity & magnetism this spring is going to suck so much harder, taught by a man who simply loves calculus and has no qualms about banishing calculators with more than simple functions.
P.S. Virginia is down, Allen needs to stfu!
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Cyan~Fire I'll count you!

Age:37 Gender: Joined: Jul 14 2003 Posts: 4608 Location: A Dream Offline
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Posted: Wed Nov 08, 2006 11:22 am Post maybe stupid Post subject: |
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MGB wrote: | Well, it is my forums, and I do try to visit daily. Even so, I'm still not number one by a long shot. |
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Agurus Server Help Squatter

Age:39 Gender: Joined: May 05 2004 Posts: 353 Location: SSCI Halo Offline
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Posted: Wed Nov 08, 2006 9:20 pm Post maybe stupid Post subject: |
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Pardon my handwriting, but here is my work any thing you guy see wrong?
tada
2.JPG - 65.97 KB
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Cyan~Fire I'll count you!

Age:37 Gender: Joined: Jul 14 2003 Posts: 4608 Location: A Dream Offline
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Posted: Thu Nov 09, 2006 12:39 am Post maybe stupid Post subject: |
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Working on a response, I'll edit in a few minutes...
Edit: OK, here's what I have to say. I'm tired right now and I need to get up early tomorrow (... for Physics) so I'll check it in the morning and I'll actually try to solve the problem.
comments.jpg - 98.88 KB
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Agurus Server Help Squatter

Age:39 Gender: Joined: May 05 2004 Posts: 353 Location: SSCI Halo Offline
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Posted: Thu Nov 09, 2006 8:34 am Post maybe stupid Post subject: |
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Fr= Force Reaction, same as Fn basically.
2w= weight of bar
w= weight of ball (go weights from problem)
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Cyan~Fire I'll count you!

Age:37 Gender: Joined: Jul 14 2003 Posts: 4608 Location: A Dream Offline
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Posted: Thu Nov 09, 2006 12:27 pm Post maybe stupid Post subject: |
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OK, well you're right, it is the normal force. I guess you can call it whatever you want when you're doing your own work, but it would probably be good to call it the normal force when showing your work to others (such as us or your teacher).
So... everything else I said still stands. I realize that w is the weight of the ball (and the bar, reread the problem). So why did you multiply the coefficient of friction by the weight to get the frictional force? Why is the normal force even in (what I'm assuming is) your torque equation?
Finally, you didn't answer my question. What did you pick for your axis?
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Quan Chi2 Member of "Sexy Teenagers that Code" Group

Age:34 Gender: Joined: Mar 25 2005 Posts: 860 Location: NYC Offline
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Posted: Fri Nov 10, 2006 4:41 pm Post maybe stupid Post subject: |
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I wish I knew how to add.
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