What is Shell: Definition and 783 Discussions

CONFIG.SYS is the primary configuration file for the DOS and OS/2 operating systems. It is a special ASCII text file that contains user-accessible setup or configuration directives evaluated by the operating system's DOS BIOS (typically residing in IBMBIO.COM or IO.SYS) during boot. CONFIG.SYS was introduced with DOS 2.0.

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  1. B

    Finding Files with Capital Letters Only in Shell Script

    Homework Statement I have a really basic task in which I have to make a shell script, pipe ls to grep and only output files that has capitals in it, meaning no lower case, no symbols, no numbers, etc. I've been searching all over google and my notes but I've been doing this over an hour...
  2. M

    Electric field outside a long cylindrical shell

    Homework Statement A long cylindrical shell of radius R = 12.3 cm carries a uniform surface charge 4.60E-6 C/m2. Using Gauss's law find the electrical field at a point p2 = 16.5 from the center of the cylinder. Homework Equations EA=q/epsilon0 The Attempt at a Solution This is what...
  3. M

    Volumes of Rotating Functions: Shell vs. Washer Method

    Is there a general rule when to use the shell or washer method when working with calculating volumes of functions rotating about an axis? For instance should I use the shell method when rotating about the y-axis and use the washer method when rotating about the x?
  4. C

    Volume Shell Method: Setup & Evaluation

    Homework Statement Use the shell method to set up and evaluate the integral that gives the volume of the solid generated by revolving the plane region about the y-axis. y = √x Homework Equations V=2∏∫p(x)h(x) dx a=0 b=8 The Attempt at a Solution V=2∏∫(x)(√x)dx a=0 b=8...
  5. T

    On a Lemma of the Shell Theorem

    I am concerned regarding a lemma of the shell theorem. Specifically, I am concerned with the idea that due to the vector nature of the forces, that one can simplify this: into this: Could somebody precisely explain why we're allowed to multiply in the \cos \varphi in the second equation?
  6. P

    Exploring Gauss' Law of Flux & Newton's Shell Method for Hollow Spheres

    While I do see how this makes sense using Newton’s Shell method, I don’t see how Gauss’ Law of Flux for a closed surface proves the same thing. Both Gauss’ Law of Flux and Newton’s Shell method make perfect sense to me in showing that when dealing with a point outside the hollow conducting...
  7. R

    Little help to construct the 4 node-quad shell stiffness matrix

    hi all, Actually I'm looking for little help and kinda confirmation, in order to verify that I understood the logic of construing the stiffness matrix. I got the logic of how to construct the stiff matrix for bending and membranes to some level, although FEM books suggests to simply combine...
  8. Q

    Consider a long cylindrical dielectric shell of inner cross-sectional

    Homework Statement consider a long cylindrical dielectric shell of inner cross-sectional radius a , outer radius b, and constant volume charge density raw zero . THe potenials of the ineer and outer surfaces of the cylindrical shell are held at potentials 0 and V respectively as shown in the...
  9. S

    Moment of Inertia of a Hemispherical Shell

    Prompt: Find the moment of inertia about the z-axis of the hemispherical shell of problem II-6. Additional Info.: -Problem II-6 states: the distribution of mass on the hemispherical shell z=(R^2-x^2-y^2)^1/2 is given by o(x,y,z) = (o/R^2)(x^2+y^2) where σ0 is a constant. Find an expression in...
  10. I

    Dipole moment of a spherical shell

    Homework Statement I'm trying to do problem 3.28 in griffith's electrodynamics. The problem statement is, to find the dipole moment of a spherical shell with charge distribution σ = kcosθ The way I tried to do it was to use the definition of dipole moment, which griffith defines as P=...
  11. Z

    Proof like Shell theorem for non-spherical objects?

    Is there one out there? Do we have any reason to believe we can treat other objects like point masses as well? I ask because if you consider line-world, and there was a 4m segment with uniform density 3kg/m located with it's left end at (3), the center of mass would be at (5), and I am...
  12. A

    Solving for Linear Speed of Spherical Shell After Rolling

    Homework Statement A thin spherical shell lying on a rough horizontal floor is hit by a cue in such a way that the line of action of force passes through the centre of the shell.as a result the shell starts moving with a linear speed v without any initial angular velocity.find the linear speed...
  13. T

    Electric potential inside a spherical shell

    Say we have a spherical shell of outer radius b and inner radius a. The shell has a total charge +3q and at it's center is a point charge of charge -q. I know that the E field for r>b would simply be: E = (3q-q)/(4πr^2ε0) and thus the electric potential inside the shell must be the same as the...
  14. J

    A shell explodes into three fragments of equal masses.

    Homework Statement A shell explodes into three fragments of equal masses. If two fragments travel at right angles to one another with equal speeds, 'v', what is the direction and speed of the third fragment? Homework Equations doing ratios? The Attempt at a Solution i don't know...
  15. G

    Moment of Inertia of a Conical shell

    Homework Statement Given that the conical shell has uniform density and thickness is made of one sheet, has mass M, height h, and base radius R, derive the moment of inertia about its axis of symmetry. Homework Equations I = MR^2 for a ring about its central axis. I = ∫dI - my approach The...
  16. Spinnor

    What causes this shell of light around the Earth in this vedio?

    In the following web page with imbedded video, play and stop the video at the 30 second mark (the video is about 1/3 of the way down the following link). http://blogs.scientificamerican.com/observations/2011/11/14/the-best-video-of-earth-from-space-ever-made/ Why does there appear to be a thin...
  17. B

    Does the Principal Quantum Number Refer to the Electron Shell?

    I was wondering, does the principal quantum number refer to the electron shell.
  18. O

    Question About Bohr's Quantified Shell Model

    I'm sure this has a straightforward explanation and am hoping someone can answer it for me. Looking at this diagram of Bohr's quantified shell model of the atom: http://library.thinkquest.org/C005775/Theory/oldtheory_section3.html ...I don't understand what is preventing the electron...
  19. W

    Understanding the Nucleus Shell Model

    hi please explain what is nucleus shell model?
  20. W

    Why is the nuclear shell model build around single particle motion?

    Hi everyone For the past few months I have been learning about the nucleus and the nuclear shell model. The experimental evidence for a shell structure is overwhelming and easy to understand. It is also quite straight forward to obtain the correct shell closures (magic numbers) using a 3d...
  21. F

    Help with coding my own shell in C, Unix environment

    Homework Statement Need to write my own shell in C for a Programming assignment. It must also support piping, redirection, and appending. Homework Equations The professor provided a preliminary version of the program that supports piping, but not redirection of either input or...
  22. mishima

    Moment of inertia of hemispherical shell

    Homework Statement The distribution of mass on the hemispherical shell: z=(R2-x2-y2)1/2 is given by σ(x,y,z)=(σ0/R2)(x2+y2) where σ0 is a constant. Find the moment of inertia about the z-axis of the hemispherical shell. Homework Equations I=∫r2dm The Attempt at a Solution...
  23. Q

    How does GR handle metric transition for a spherical mass shell?

    This is really a continuation from another thread but will start here from scratch. Consider the case of a static thin spherical mass shell - outer radius rb, inner radius ra, and (rb-ra)/ra<< 1, and with gravitational radius rs<< r(shell). According to majority opinion at least, in GR the...
  24. Q

    Spherical Mass Shell - What Actually Happens?

    In another thread I posed basically the folowing problem: Take the case of a stationary, non-rotating thin spherical shell of uniform area mass density - outer radius rb, inner radius ra, with (rb-ra)/ra << 1. There is consensus opinion that everywhere exterior and down to rb, spacetime is that...
  25. B

    Potential energy of an hemispheric shell

    Homework Statement Given that the hemisphere has a charge +Q distributed through its surface with radius a. Find the electric potential on any point on z axis (the plane of the hemisphere is oriented in positive z direction).Homework Equations \phi = \int\frac{kQ}{|R-R'|}*ds (surface integral)...
  26. I

    Volumes with Cylindrical Shell Method

    Homework Statement Use the method of cylindrical shells to find the volume of the solid obtained by rotating the region bounded by the given curves about the x-axis. y= 4x2, y=-2x+6 Homework Equationsy= 4x2, y=-2x+6 These 2 equations meet at x= -3/2 and x=1 integral from a to b of...
  27. W

    Potential difference inside a spherical shell

    Homework Statement A top half of a spherical shell has radius R and uniform charge density sigma. Find the potential difference V(b)-V(a) between point b at the north pole, and point a at the center of the sphere. Homework Equations The Attempt at a Solution \oint E ds =...
  28. L

    Gauss Law Problem With A Spherical Conductive Shell

    You are a hollow metallic sphere of inner radius r1, and outer radius r2. Inside is a charge of magnitude Q and a distance d<r1 from the centre. First I need to draw the electric field lines for regions r<r1, r1<r<r2, and r2<r Since the sphere is a conductor the only place where there is...
  29. S

    ANSYS Mechanical- Shell and Link

    Hey guys, I am currently working on a project and need to model the tubing configuration as shown in the first attachment. Experimental testing has been completed and I have detailed data for the strain and vibration velocity as required. I need to model this in ANSYS to compare the...
  30. D

    Calculating Volume of Rotation with Shell Method for Region Underneath Graph

    Homework Statement Use the shell method to calculate the volume of rotation about the x-axis for the region underneath the graph. y=\sqrt[3]{x}-2, 8\leqx\leq27 Homework Equations I was taught that I would set up the integral by using the area which would look something like...
  31. E

    Singularity or just a very small, massive shell?

    The nature of a black hole is that gravity attracts objects at a speed faster than light making it impossible for them to be able to escape but if the object is accelerating towards the black hole it would slow down and become more massive the close it got because it is approaching the speed of...
  32. D

    Expressing a potential inside a spherical shell as

    Homework Statement The potential inside a spherical shell is given by: V_{-}(x,y,z)= \frac{V_0}{R^2}(6z^2-3x^2-3y^2) P_n(\cos(\theta )) where \theta is the polar angle. The potential on the surface carries a surface charge density \sigma. Besides this, ther's no other charges and no outher...
  33. D

    Potential inside NON-Conducting hollow spherical shell

    Hi Guys, Suppose we have a spherical shell with charge density on the surface \sigma and radius R. The potential inside the shell is given by: V_(x,y,z) = \frac{V0}{R^{2}}(6z^2+ax^2+by^2) It is assumed, that the potential is rotational symmetric around the z-axis inside and outside the...
  34. D

    Potential of Concentric Cylindrical Insulator and Conducting Shell

    An infinitely long solid insulating cylinder of radius a = 5.3 cm is positioned with its symmetry axis along the z-axis as shown. The cylinder is uniformly charged with a charge density ρ = 45 μC/m3. Concentric with the cylinder is a cylindrical conducting shell of inner radius b = 14.2 cm, and...
  35. P

    Charge Distribution on Conducting Spherical Shell

    Homework Statement A conducting spherical shell that has zero net charge has an inner radius R1 and an outer radius R2. A postive point charge q is placed at the center of the cell. The 1st part was to find the electric fields at the 3 diff places. The part I need help on is where we have to...
  36. J

    Newton's Shell Theorem Question

    Hello everyone! I'm a math major taking a university physics course, and I have a question about the proof that perfectly spherical objects have equivalent gravitational force as a point mass located in the center. The proof in question can be seen in one form at...
  37. S

    Rocket Propelled Shell - Space

    Hello I am currently studying for a BA iin mech eng. Now, i have been thinking recently, is it possible to produce a lightweight artillary shell, that can contain a solid state rocket fuel, and a compressed oxygen canister? If so, would it not be all that impossible to fire this 'shell'...
  38. H

    Why Does Charge Flow to Outer Spherical Shell?

    So there are two concentric conducting spherical shells one with radius R and another 2R with charge +Q and +2Q respectively... Now the two are connected by a conducting wire. Why does the entire charge flow to the outer shell? Please clarify my doubts. I will be grateful.
  39. J

    Calculating volumes by shell and slicing

    Homework Statement The area under the graph of the function y = cos inverse x on the interval [0; 1] is rotated about the x-axis to form a solid of revolution. (a) Write down the volume V of the solid as a de nite integral with respect to x according to the disc/slicing method. Do NOT...
  40. F

    I can't believe I am not getting this, shell method

    Homework Statement Let's say I have the area bounded by y_1 = \sqrt{x} and y_2 = x^2 in (0,1). Rotate that about the x-axis, find that volume of solid. The Attempt at a Solution Which one is right? \int_{0}^{1} \pi (x^2 - \sqrt{x})^2 dx \pi \int_{0}^{1} x^4 - x dx I think...
  41. H

    Atomic Shell Theory: Bohr-Sommerfeld model

    This is a very naive question. But I think, it's an important point that has been unattempted in textbooks. The question is: How far should one trust the Bohr-Sommerfeld model or the atomic shell theory for all elements in the periodic table? This question generally comes in mind, since...
  42. M

    Surface Integral over Half Shell

    From Div,Grad, Rot and all that Disclaimer: Sorry, why do the Latex tags not work? Homework Statement "An electrostatic field is given by \vec{E} = \lambda (\hat{\vec{i}}yz + \hat{\vec{j}}xz + \hat{\vec{k}}xy), where \lambda is a constant. Use Gauss' law to find the total charge enclosed by a...
  43. C

    Derivation of the moment of inertia eqn for a thin spherical shell

    So I've been trying to derive the moment of inertia equation for a thin spherical shell and I've slammed into a dead end algebraically. I was able to derive an equation for a hollow sphere: I = (2/5) M (Ro^5 - Ri^5)/(Ro^3 - Ri^3) where Ro is the distance to the very outside of the sphere...
  44. M

    Do all five orbitals of the d-sub shell have equal energies?

    See Title
  45. C

    Currents in a Wire and a Cylindrical Shell

    Homework Statement Hello PF, first time poster here. I don't normally ask for help on the internet, especially for homework, but I've visited this website several times and I've seen nothing but good as I've looked at everyone else being helped, so I decided it'd be worth a try. :) So here's...
  46. A

    What is the relation between a shell and a solid sphere?

    Homework Statement Homework Equations The Attempt at a Solution What is the relation between a shell and a solid sphere? Can you give me some hints?
  47. Y

    Electric field in a spherical shell

    Homework Statement A -5-nC point charge is located at the center of a conducting spherical shell. The shell has an inner radius of 2 m, an outer radius of 4 m, and a charge of +7 nC. (Let the radially outward direction be positive.) (a) What is the electric field at r = 1 m? (Indicate the...
  48. S

    Charge inside conducting shell

    Homework Statement Inside a metal conducting shell of radius R there is a negative charge q at a distance a from the center M. The shell is brought up to a potential V. What is the surface charge on the inside and outside of the conductor? The Attempt at a Solution I'm not sure if this...
  49. D

    Shell element contact problem

    Hello All, I am facing some problem while defining contact between shell elements. My problem is as below. 1. Two thin layers (thickness of 10^-5 m each) of composite material are bonded to a solid material like foam. 2. A third layer of the same thickness comes in contact for a certain...
  50. A

    How Does Mesh Refinement Affect Shell Deformation in ANSYS?

    Homework Statement A square plate of edge length L = 1 m, thickness t = 5 cm, is fixed on two edges. The other two edges are free. A load of F = 10 kN is applied at the corner opposite that where the fixed edges intersect. Use shell elements to compute the deflection at the loaded corner...
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