I think the mass terms should cancel out, since you're trying to find the speed where angular acceleration overcomes the frictional acceleration, and you're left with just a function of angular velocity and frictional coefficientsBevo wrote:
I misread the turntable problem, the mass is some distance from the center and we're supposed to find the time it takes for it to start movingS.Lythberg wrote:
Angular stuff is the same, all the same equations, just with radians/second instead of meters/second.Bevo wrote:
i've got a "racecar" on a raised curve problem, where I have to find the max velocity it can achieve without slipping outwards. There's friction involved too. No idea how to set it up -the book has a similar problem, but it includes no friction and therefore confuses me. I don't know at which point to include friction in the calculations, or if I should include the x component of the mg, or if that's nullified by centripedal acceleration...
also got a block at rest in the middle of a turntable, and given a friction and angular acceleration, want to know at what point it falls off the table. again no idea how to deal with angular anything because it was never taught anywhere
we don't get a mass though, which is confusing...
Since you are trying to prevent outward slippage, you know the force of gravity is insufficient to counteract the centripetal force, and so the force of friction being analyzed is working in the same direction as the gravity. Since the object isn't actually moving, you'd use static friction, and so the expression becomes:Bevo wrote:
I misread the turntable problem, the mass is some distance from the center and we're supposed to find the time it takes for it to start movingS.Lythberg wrote:
Angular stuff is the same, all the same equations, just with radians/second instead of meters/second.Bevo wrote:
i've got a "racecar" on a raised curve problem, where I have to find the max velocity it can achieve without slipping outwards. There's friction involved too. No idea how to set it up -the book has a similar problem, but it includes no friction and therefore confuses me. I don't know at which point to include friction in the calculations, or if I should include the x component of the mg, or if that's nullified by centripedal acceleration...
also got a block at rest in the middle of a turntable, and given a friction and angular acceleration, want to know at what point it falls off the table. again no idea how to deal with angular anything because it was never taught anywhere
we don't get a mass though, which is confusing...
Fgrav+Ffric - Fcent = 0
It is set equal to zero because the forces will perfectly offset each other at the maximum velocity the car can achieve.
From this, define the forces properly, as you should be able to do, and solve for velocity.
Right, thanks for the help on those.
I got 2 more today
one, theres a 3kg block moving on the x-axis by a force F(x) = 5x2 - 1.4
at 1.4m it's moving to the right with a speed of 4.4m/s
find speed at 2.8m
So i took the integral of the acceleration, which was 1/3F(x) which gave me 1/3((5/3)x3 - 1.4x). Plugging in the x and velcocity for the block at 1.4m, it gives me a constant C = 3.34 (or V0).
Then plugging in x=2.8 to my resultant equation I get an answer of 14.229 m/s, which seemed reasonable. However, it's incorrect. Halp!
edit: also, if two springs along x=0 attached to an object and then pulled at x= some constant, then let go, would the KE of the object equal the total potential energy of the springs? Or would the energy in the "y" direction cancel out somehow, and I'd have to take the cos of the angle formed?
I got 2 more today
one, theres a 3kg block moving on the x-axis by a force F(x) = 5x2 - 1.4
at 1.4m it's moving to the right with a speed of 4.4m/s
find speed at 2.8m
So i took the integral of the acceleration, which was 1/3F(x) which gave me 1/3((5/3)x3 - 1.4x). Plugging in the x and velcocity for the block at 1.4m, it gives me a constant C = 3.34 (or V0).
Then plugging in x=2.8 to my resultant equation I get an answer of 14.229 m/s, which seemed reasonable. However, it's incorrect. Halp!
edit: also, if two springs along x=0 attached to an object and then pulled at x= some constant, then let go, would the KE of the object equal the total potential energy of the springs? Or would the energy in the "y" direction cancel out somehow, and I'd have to take the cos of the angle formed?
Last edited by Bevo (2010-03-03 19:17:34)
[(5/9)x3-(7/15)x]2.81.4
Shouldn't you just evaluate that to find it, knowing that the constant of integration is v(1.4)=4.4
Doing that, I get 10.0178+4.4=14.4178. Does that work?
Regarding the second problem, I vaguely remember doing it last semester, and I do remember using trigonometry somewhere in the math.
Shouldn't you just evaluate that to find it, knowing that the constant of integration is v(1.4)=4.4
Doing that, I get 10.0178+4.4=14.4178. Does that work?
Regarding the second problem, I vaguely remember doing it last semester, and I do remember using trigonometry somewhere in the math.
Last edited by nukchebi0 (2010-03-03 19:26:53)
I don't want to find the velocity over the period between 2.8 and 1.4, I just want to find the velocity at the specific position of 2.8m. Isn't what you gave me the average v between the two?nukchebi0 wrote:
[(5/9)x3-(7/15)x]2.81.4
Shouldn't you just evaluate that to find it, knowing that the constant of integration is v(1.4)=4.4
Doing that, I get 10.0178+4.4=14.4178. Does that work?
Isn't the area under the acceleration function equivalent to the change in velocity, and isn't the change in velocity plus the velocity at the first pont of the interval equal to the velocity at the second point of the interval?
I also found the answer to the question from last semester that is similar to yours. Do you want me to give it to you?
I also found the answer to the question from last semester that is similar to yours. Do you want me to give it to you?
Last edited by nukchebi0 (2010-03-03 19:32:10)
Sure.
Also I checked your math and it seemed to be correct, however the answer is still wrong. :\
do you know the answer to my edit also, re: springs?
Also I checked your math and it seemed to be correct, however the answer is still wrong. :\
do you know the answer to my edit also, re: springs?
ed: I see an error...
F(x) is the force over a distance, not over time
therefore the acceleration is over distance, and what we thought was velocity was really velocity squared?
I'm so fucking confused.
F(x) is the force over a distance, not over time
therefore the acceleration is over distance, and what we thought was velocity was really velocity squared?
I'm so fucking confused.
Does acceleration as a function of position not directly correlation to dv/dx? I don't have my physics book with me, so I can't check. That is the only thing I can foresee as messing up the calculations.
I meant the answers I have are for the second one.
I meant the answers I have are for the second one.
Last edited by nukchebi0 (2010-03-03 19:45:18)
das link is brokennukchebi0 wrote:
Does acceleration as a function of position not directly correlation to dv/dx? I don't have my physics book with me, so I can't check. That is the only thing I can foresee as messing up the calculations.
I meant the answers I have are for the second one.
http://static.bf2s.com/files/user/26506 … 0Pset3.jpg
That is primarily because I'd tried to convert a pdf directly to an image file in order to use the image upload. If there a good hosting site I can use?
http://drop.io/Bevosfiles#nukchebi0 wrote:
That is primarily because I'd tried to convert a pdf directly to an image file in order to use the image upload. If there a good hosting site I can use?
warman-m4a
classsic - "You may not karma the same person in a 24 hour period"
Question 7.49 is the only one which concerns you. If you could, don't spread it to anyone else and delete it when you finish.
Last edited by nukchebi0 (2010-03-03 20:02:18)
after looking through that I got confused and used the answer I made earlier, turned out to be correct.
Now the only one I have left is the 3kg block one...
so the integral of a(x) is v2, is it not? I still have no clue how to approach that as a function of distance. The whole problem is confusing.
Now the only one I have left is the 3kg block one...
so the integral of a(x) is v2, is it not? I still have no clue how to approach that as a function of distance. The whole problem is confusing.
The equation a*dx=v*dv is all that you need. A is a function of x, so it integrates cleanly, as does v*dv. This link should clarify and guide your solution to the question.
following this now, praying it clears stuff upnukchebi0 wrote:
The equation a*dx=v*dv is all that you need. A is a function of x, so it integrates cleanly, as does v*dv. This link should clarify and guide your solution to the question.
thanks
ed: would i still eval from 2.8 to 1.4?
Last edited by Bevo (2010-03-03 20:36:35)
i cant be bothered to do the next 2000 words, someone fill it for me please
"When postcolonial theory emerged in the 1980’s, much of the criticism that was directed against the ‘new’ discipline and its advocates came from Marxist critics. Evaluate at least two Marxist critiques of postcolonialist theory."
thanks
"When postcolonial theory emerged in the 1980’s, much of the criticism that was directed against the ‘new’ discipline and its advocates came from Marxist critics. Evaluate at least two Marxist critiques of postcolonialist theory."
thanks
Last edited by Uzique (2010-03-03 20:38:46)
libertarian benefit collector - anti-academic super-intellectual. http://mixlr.com/the-little-phrase/
Everything is perceived, nothing can be proven.
Essay done.
Essay done.
yeah go back to your this-is-right, this-is-wrong textbook, faggot
heaven forbid should you apply your brain to something else other than plugging numbers into pre-defined formulas and theorems
heaven forbid should you apply your brain to something else other than plugging numbers into pre-defined formulas and theorems
Last edited by Uzique (2010-03-03 20:44:48)
libertarian benefit collector - anti-academic super-intellectual. http://mixlr.com/the-little-phrase/
love you too hunUzique wrote:
yeah go back to your this-is-right, this-is-wrong textbook, faggot
heaven forbid should you apply your brain to something else other than plugging numbers into pre-defined formulas and theorems
<3
haha, we all know your type of work requires a higher level of thought but high levels math and shit is hard either way.Uzique wrote:
yeah go back to your this-is-right, this-is-wrong textbook, faggot
Angola, amirite?
"New colonies aren't needed when Marxist countries co-exist and work with one another. The capitalist system fails when countries seek to enrich themselves from the work of another, but at this point there are enough Marxist countries to be self sustaining. With the new world order present in every climate and region now, Marxism will be viable as a world model for sustainable and progressive growth"
[fuck, i lost count . . .]
"New colonies aren't needed when Marxist countries co-exist and work with one another. The capitalist system fails when countries seek to enrich themselves from the work of another, but at this point there are enough Marxist countries to be self sustaining. With the new world order present in every climate and region now, Marxism will be viable as a world model for sustainable and progressive growth"
[fuck, i lost count . . .]
angola is an example... as is mozambique... south africa... latin america... east timor... india... err pretty much anywhere with a colonial past. ive got to evaluate how the two disciplines dialogically critique one another in theoretical, abstract ways though. historical dialecticism and hegelian-marxian conceptions of 'progress' and all that LOVELY boring shit. i hate writing essays on literary theory, the worst part of this degree by a long mile.burnzz wrote:
Angola, amirite?
"New colonies aren't needed when Marxist countries co-exist and work with one another. The capitalist system fails when countries seek to enrich themselves from the work of another, but at this point there are enough Marxist countries to be self sustaining. With the new world order present in every climate and region now, Marxism will be viable as a world model for sustainable and progressive growth"
[fuck, i lost count . . .]
Last edited by Uzique (2010-03-03 20:48:11)
libertarian benefit collector - anti-academic super-intellectual. http://mixlr.com/the-little-phrase/
essentially literary theory is considered the stepping stones of your degree.Uzique wrote:
angola is an example... as is mozambique... south africa... latin america... east timor... india... err pretty much anywhere with a colonial past. ive got to evaluate how the two disciplines dialogically critique one another in theoretical, abstract ways though. historical dialecticism and hegelian-marxian conceptions of 'progress' and all that LOVELY boring shit. i hate writing essays on literary theory, the worst part of this degree by a long mile.burnzz wrote:
Angola, amirite?
"New colonies aren't needed when Marxist countries co-exist and work with one another. The capitalist system fails when countries seek to enrich themselves from the work of another, but at this point there are enough Marxist countries to be self sustaining. With the new world order present in every climate and region now, Marxism will be viable as a world model for sustainable and progressive growth"
[fuck, i lost count . . .]
we (the world) need to work together specifically by using some of these already applied theories to help causes.