Cut Definition and 266 Threads

  1. S

    Where is the mistake in my probability calculation for a 20cm string cut?

    I want to ask about part (c). This is what I did: the length of the shorter piece should be 8 ≤ X < 10 so P (8 ≤ X < 10) = 2 . (1/20) = 1/10 But my teacher said the correct answer is 2/10. Where is my mistake? Thanks
  2. Cody Livengood

    B What if we cut out the Big Bang and inflation?

    Are the Big Bang and inflation really needed to account for the large-scale structure of the universe, nucleosynthesis, baryon acoustic oscillations, and the anisotropies of the CMB? Can the universe not begin in an already expanded state and still have all those things happen just the same...
  3. Svelte1

    Why do I have to take the moment at the cut to get the right answer?

    Every time I have taken moments before I have been able to solve for the required unknown regardless of what point I choose, unless there is more than 1 unknown! However I tried taking moments from the far left point load of 97.5 this time and I get the wrong answer. I don't understand why...
  4. H

    Proving a property of a Dedekind cut

    A Dedekind cut is a pair ##(A,B)##, where ##A## and ##B## are both subsets of rationals. This pair has to satisfy the following properties A is nonempty B is nonempty If ##a\in A## and ##c \lt a## then ##c \in A## If ##b \in B## and ## c\gt b## then ##c \in B## If ##b \not\in B## and ## a\lt...
  5. bigmike94

    Need to cut back on the time I spend self-studying each Intro Mechanics chapter

    These are all the chapters for introductory mechanics in my textbook. What I have been doing is reading the chapter then following it up with watching a tonne of lectures and worked examples on that topic and attempting to do the problems. I’m on Applying Newton’s laws and I’ve been studying it...
  6. D

    Define a Dedekind cut and show the given set is(n't) a Dedekind cut

    a) a subset ##L\subset \mathbb{Q}## is a Dedekind cut if ##L## is proper, ##L## has no maximal element, and $$\forall a,b\in \mathbb{Q}, [(a<b)\land( b\in L)\Longrightarrow a\in L]$$ b) Is ##P=\{x^4|x\in L\}## a Dedekind cut? P is proper: $$(a\in L)\Longrightarrow (a^4\in P)\Longrightarrow...
  7. philo

    How much pressure in PSI was needed in the Ancient World to cut stones?

    Was watching a video on the the Great Pyramid of Giza and it got me wondering how one might cut one of the stones. Doing a couple google searches, I thought that a Venturi pump would likely be the means by which the stones were cut. The problem being how would they get a large enough psi...
  8. W

    Construction How to cut a board so that it can be bent spherically?

    Example of normal application: What i'd like to achieve: More information: Wedi board serration either straight or angled depending on radii wanted. It's also possible to serrate outwards to achieve radii less than 200mm (example from ThermaSheet) Any ideas on how to do this?
  9. Y

    2 bodies spining and cut in the middle

    M1 and M2 are rigid bodies that connected. they spin freely around the Z-axis. At a certain time (we will set t=0) when the bodies are in the state described below, the bodies disconnect from each other when each of the bodies is given a speed addition in the direction of the X(V1 and V2 axis...
  10. Fervent Freyja

    Reasons my internet/cable line was cut?

    Don’t know exactly where to ask this, so I’ll try here first. Okay, so a few weeks ago my internet went out. I ended up receiving a new modem in the mail the next day after I called. It didn’t work. I was finally able to be home for a technician to check it out this week. He told me that...
  11. A

    Can You Cut Geometries in GATE Like in MCNPX?

    Hi every one. As you all know, in MCNPX you can define different geometries and cut them with each other and create new irregular geometries. For example, you can cut a sphere with a cylinder and create a semi spherical geometry within the cross section of cylinder. now Here is my question: is...
  12. A

    Election of cut placement for Shear flow -- Hibbeler's example

    Hello. I am reading Hibbeler's Mechanics of Materials (ninth edition). Example 7.5 computes shear flow at a segment where there are nails attached to different boards. He chooses a cut like the one shown here: And gets (by symmetry between C and C') the shear flow q computing the first moment...
  13. K

    MHB Hectares and kilometres - how many days to cut 295 hectares

    Hello! I am new to math forums and am not even sure I’m in the right thread but will give it a go! I am trying to determine how many days it will take to mow 295 hectares when my mower has a blade 12’ wide and can move at 4km/hour. Attached is what I believe to be correct but am uncertain if you...
  14. MidgetDwarf

    Dedekind Cut, as stated by Richard Dedekind

    Greetings. I was wondering if anyone knew who gets the credit for the modern treatment of Dedekind cuts using what are commonly called lower cuts or upper cuts. Since one can show that a lower/ upper cut characterizes the other, so we can just work freely with either lower or upper cuts, and...
  15. tworitdash

    A Integrating a function of which poles appear on the branch cut

    I have a complicated function to integrate from -\infty to \infty . I = \int_{-\infty}^{\infty}\frac{(2k^2 - \Omega^2)(I_0^2(\Omega) + I_2(\Omega)^2) - \Omega^2 I_0(\Omega) I_2(\Omega)}{\sqrt{k^2 - \Omega^2}} \Omega d\Omega Where I0I0 and I2I2 are functions containing Hankel functions as...
  16. M

    Do plants get any negative sensations when we cut them?

    Homework Statement:: I was wondering when I break a branch of a tree, does it feel any pain or does it feel the same way I feel when I trim my nails or cut hair? Relevant Equations:: I tend to think that the latter is true as trees don't have brains or neurons. Thanks <mentor moved to...
  17. Grinkle

    Interest rate cut vs health policy - how are they consistent?

    Cutting interest rates is intended to change people's behavior in favor of economic growth driving activity. In the main this necessarily involves an increased amount of leaving ones home and going to work. The novel CV itself is not impacting the economy - it is the various policies to combat...
  18. bhobba

    I What Do Most Physicists Call the Quantum-To-Classical Cut?

    Hi All This is just a dumb question. I have usually called the the Quantum/Classical cut the Von-Neumann cut because Von-Neumann's classic text was the first serious QM book I read - nearly 40 years ago now - seems like yesterday. Recently I noticed in some of the papers I have been...
  19. V

    What Is the Shear Strength of a Cut I-Beam in a Cantilevered Structure?

    Hello, I'm in the process of building a 2 story townhome project and had a question on a beam. The structural engineer is calling for a cut I-beam on top foundation which spans over the garage (10') and the load will be placed on just the top flange (see attached). The structure will cantilever...
  20. Like Tony Stark

    Finding angular velocity for a rope to be cut

    I wrote Newton's equations for each body (I took ##x## as the axis aligned with the tension) ##m_1##: ##x)f*_1 -T_1+T_2=0## Where ##f*_1=\omega ^2 r_1## ##m_2## ##x)f*_2 -T_2=0## ##x)f*_2=T_2## Where ##f*_2=\omega ^2 r_2## I wrote that ##T_2=1100 N## and solved for ##\omega##, and I got...
  21. sdefresco

    Electrodynamics: Conducting sphere of radius R cut in half

    Summary: Electrodynamics: Conducting Sphere cut in half to form a gap, and a charge q is placed on the first half-sphere. Find all four σ. A sphere of radius R is cut in half to form a gap of s << R (ignore edge effects) - the first hemisphere is charged with q, and the second hemisphere is left...
  22. A

    Interference fringe pattern on a thin cut cylinder slice

    A thin slice is cut out of a glass cylinder along a plane parallel to its axis. The slice is placed on a flat glass plate as shown in the figure. The observed interference fringes from this combination shall be ______. My thoughts The thin slice will act as thin film but of half cylindrical...
  23. A

    Troubleshooting Geometry Cutting with Vised X_225 and MCNPX 2.7

    Could someone tell me why this happens when I cut geometry? The program that i used is Vised X_225 and my mcnpx version is 2.7 Sorry for my posts, I'm really in trouble.
  24. R

    B Is the Universe a 3D Cut of a 4D object?

    I have just simple Knowledge, but recently a question came To my mind. An Entity Living in 2d Space cannot Directly Observe a sphere, but rather a Circle Changing its Size when a sphere is traversing trough the observable 2d plane. Similar, a 4d sphere would Appear To us as 3d sphere Changing...
  25. T

    I Understanding the "branch cut argument"

    http://web.williams.edu/Mathematics/sjmiller/public_html/302/coursenotes/Trapper_MethodsContourIntegrals.pdf See Type 5 Integrals. I don't understand why J is equal to the original real integral multiplied by a factor of ##2\pi i##. I think the ##2\pi i## comes from the fact that as you go...
  26. J

    How to cut down 12 volts to 1.5 volts

    I know one can use a LM317 to cut 12 volts dc to 1.5 volts but can one use resistors? I have a wall clock that runs a small motor to wind spring and it powered by a c battery you can run on more voltage without out damage to any thing as it only run for 1 second every 2 minutes. I tried a 30 ohm...
  27. E

    What is the best material to use to cut galvanized sheet metal?

    hello every one can you help me in selecting the material to be used in the blade of cutting machine which will be used to cut galvanized sheet metal
  28. TheQuestionGuy14

    B What is the GZK Cut Off Point and why does it happen?

    What is the GZK Cut Off point? I've seen an article stating that Prof. Silas Beane says a sort of 'lattice', an energy limit, which may suggest we are living in a matrix. But that can't be right? Can it? What actually causes it and why does it happen?
  29. K

    Maximization problem — Stiffest beam that can be cut from a log

    Homework Statement Homework Equations Pitagora's: ##~a^2+b^2=c^2## Maxima/minima are where the first derivative is 0 The Attempt at a Solution $$\left( \frac{a}{2} \right)^2+\left( \frac{b}{2} \right)^2=r^2~\rightarrow~b^2=\frac{16r^2}{a^2}$$ The strength S has the proportion coefficient k...
  30. Spinnor

    SpaceX SpaceX's rival has 'genius' plan to cut rocket cost

    http://www.businessinsider.com/how-vulcan-rocket-works-united-launch-alliance-2018-2
  31. Z

    MHB Calculating Sphere Volume Cut by 2 Planes & Angle "e" & Distance "a

    I want to calculate the volume of a sphere cut by two arbitrary plane. There is a intersection angle between these two planes, which is not 90 degrees. One of these two planes is fixed and located on plane "x-o-y", and the other is perpendicular to plane "x-o-z" and moves the distance "a" from...
  32. T

    Pore Water Pressure and Shear Strength of Soil: Understanding the Relationship

    Homework Statement In the notes , I can't understand that why as the pore water pressure dissipated , the shear strength of soil will decrease secondly , why the excess pore water pressure is negative when unloading occur ? Homework EquationsThe Attempt at a Solution I think it's wrong , as...
  33. A

    How to calculate the force to cut a log?

    Good morning guys, So i want to make mechanism to cut log with diameter 5 cm and 120 cm length. So how i can calculate the force to cut this log perpendicular and paralel. What is tbe formula i can use? And how i can determine the saw thickness and rpm needed to cut this log? Thanks guys for...
  34. S

    I Drawing the contour with a branch cut

    I am trying to determine the contour required in solving part b. The branch points (poles) are at s=0 and s= -a and in between these two values, there is a branch cut. I know that the branch cut cannot be included in the contour so does this mean the poles also cannot be in the contour? Would...
  35. astrocytosis

    Induced current in a loop of wire when straight wire is cut

    Homework Statement A square loop, side a, resistance R, lies a distance s from an infinite straight wire that carries current I (pointing to the right). Now someone cuts the wire, so I drops to zero. In what direction does the induced current in the square loop flow, and what total charge...
  36. W

    Contour Integration: Branch cuts

    Homework Statement I am supposed to evaluate the contour integral of the positive branch of ##z^{-1/2}## over the following contour: I believe the answer should be 0, by Cauchy's theorem (loop encloses no poles), but my methods of parameterization have led to non-zero answers. Homework...
  37. L

    Surface area of a circular cylinder cut by a slanted plane

    Homework Statement Cylinder : x^2 + y^2 = 1 Plane that intersects above cylinder: y + z = 2 What is the surface area of the sides of this cylinder? Homework Equations dS= R1 d@ dz @ is from 0 to 2 pi z is from 0 to 2 - y dS=(Zx^2 + Zy^2 + 1)^.5 dA Where Z = 2 - yThe Attempt at a Solution I...
  38. Mr Davis 97

    I Why Does the Cut of $\mathbb{Q}$ Correspond to $\sqrt{2}$?

    Why does the cut ##(\{x \in \mathbb{Q} | x^2 \le 2 ~ \text{or} ~x < 0 \}, \{x \in \mathbb{Q} | x^2 \ge 2 ~ \text{and} ~x > 0 \})## correspond to ##\sqrt{2}##, and not just ##(\{x \in \mathbb{Q} | x^2 < 2\}, \{x \in \mathbb{Q} | x^2 \ge 2\})##? Why are the additional inequalities involving 0...
  39. E

    I Can a sheet of paper cut something if thin enough?

    I have been arguing with my friends about this question and we need some educated opinions on it. I think that if a piece of paper in thin enough it can cut something. These are the details: 1. "thin" in this case means extremely thin 2. The paper can not be used to saw or swipe( it would be...
  40. Tenebris

    Can Wolverine's Claws Defeat Superman?

    After hearing an argument on the cutting power of Wolverine, I began to wonder "could Wolverine cut, and possibly kill, Superman?" Wolverine has one of the sharpest, and strongest, cutting implements in the Marvel universe, so could he hurt the Man of Steel?
  41. Ygggdrasil

    Medical Using CRISPR to cut HIV out of infected cells

    A major impediment to curing patients with HIV is the fact that the virus integrates its DNA into the genome of the cells it infects. While antiretroviral drugs and therapies can prevent infection of new cells and kill cells that are actively producing virus, a "latent reservoir" remains that...
  42. SD das

    I Does a black hole cut the fabric of spacetime as it changes

    Einstein's general theory of relativity describes the stars distort spacetime fabric and it appears a black hole makes a hole in the spacetime fabric. It is evident that the size of a galaxy does not change due to gravity but in large scale the distance between two distant galaxies increases due...
  43. F

    Find Member Forces of AB and DE: Cut Section Method

    Homework Statement I am asked to find the member force of AB and DE Homework EquationsThe Attempt at a Solution I make an imaginary cut of the question and consider the upper part of the cut . Bur , i didnt get the same ans provided . However , when i consider the lower section of the cut , i...
  44. R

    Projectile motion (time cut in half)

    Homework Statement Two buildings A & B are each of height H as measured from the ground & are located a distance L apart. A tennis ball is shot horizontally with a velocity vo from building A such that it just hits the bottom of building B before hitting the ground. If building B is moved to...
  45. FallenApple

    How to Split a Vector into Two Parts in R?

    How do a cut a vector in R? Say I want to split a vector to two parts. One for everything less than 150 and other for everything greater than 150. I tried the cut function but it seems confusing.
  46. F

    How Does FGF sin26.6 Generate Moment About Point D in Truss Analysis?

    Homework Statement For moment about D , how could the FGF sin26.6 generate moment about D ? Homework EquationsThe Attempt at a Solution FGF sin26.6 is located above point D , right ? How could FGF sin26.6 generate moment about D ?
  47. Dembadon

    Proposed cut to publicly-funded research (NIH)

    Dr. Steven Novella contributes to a couple blogs I frequent: https://sciencebasedmedicine.org/ http://theness.com/neurologicablog/ A recent post addresses proposed budget cuts1 and the need for publicly-funded research...
  48. hdp12

    Designing a Mechanism to Cut Aluminum Bar: Help Needed!

    Hi there So we have a group design project in my mechanical systems 2 class and it basically goes as follows: design a mechanism to cut a half inch aluminum bar in half using a standard hacksaw blade and 4 AA batteries. You have to use a motor w/ input > 5000 rpm for the 'main' component we...
  49. mercenarycor

    Contour integration with a branch cut

    Homework Statement ∫-11 dx/(√(1-x2)(a+bx)) a>b>0 Homework Equations f(z0)=(1/2πi)∫f(z)dz/(z-z0) The Attempt at a Solution I have absolutely no idea what I'm doing. I'm taking Mathematical Methods, and this chapter is making absolutely no sense to me. I understand enough to tell I'm supposed...
  50. grandpa2390

    Why does this integral cut off the z component?

    Homework Statement Please don't make me post the entire question. If so, can I take a picture of the example in my textbook? I am looking at an example in my textbook where we are to check Stoke's theorem After doing the cross-product of del cross v I get (4z^2-2x)[x hat] + (2z^2)[z hat]...
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