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. J

    Getting bash shell script to do one thing if user hits enter .

    Getting bash shell script to do one thing if user hits "enter". I need to write a program that will output a line in a calendar file if a date is entered, or if no date is entered and the user just hits "enter" to ouput the line corresponding to today's date. I think that it must take the...
  2. A

    Solving Alice's Shell Script Doubt for Comparing & Generating Scores

    Hi all 30 students have sent me their answers to me in folders, "name1", "name2", ..., "name30". Each folder contains 2 outputs, "output_a.txt" and "output_b.txt" Now I have the correct answer "correct_a.txt" and "correct_b.txt" with me. I know that using the command diff, I can compare...
  3. A

    Exploring the Egg Shell Theory of the Universe

    Dear reader, Of course I searched the site to see other persons discussing the the egg shell theory, but I did not find it. So, perhaps someone can direct me to the subject. I am interested in the theory that when the universe was created in a big bang, the only part of it is the part we...
  4. Z

    Projectile motion cannon shell problem

    Homework Statement A coastal defence cannon fires a shell horizontally from the top of a 50.0m high cliff directed out to sea with a velocity of 60.0m/s. Determine the range of the shell's trajectory.Homework Equations delta x = ut (horizontally) delta y = ut + 1/2 at^2 The Attempt at a...
  5. A

    How to plot and save many data files in GNUPLOT, inside a loop in a SHELL SCRIPT

    Hi all I badly need some help... I plot a file output1.txt in the following way :: gnuplot> plot "output1.txt" using 1:2 with lines, \ plot "output1.txt" using 1:3 with lines BUT now I have many data files, output1.txt, output2.txt, output3.txt, ...,... ,output1000.txt I need to...
  6. B

    Determine the max height of the shell

    a cannon is placed on an edge of a cliff and launches shell with an initial velocity of 710m/s [35degrees above the horizontal]. the shell lands 15m below its launching position. a) determine the max height of the shell b) determine the horizontal range of the shell from the base of the cliff...
  7. F

    Mass & Velocity Components of Third Fragment in Exploding Shell | 0.4kg Shell

    A shell of mass 0.4 kg is at rest in a gravity-free environment when it suddenly explodes into three fragments. The mass and x,y components of two of the fragments is given in the table:particle mass (kg) vx (m/s) vy (m/s) [1] 0.12 25 58 [2]...
  8. L

    Thick spherical shell confirmation of solution

    Homework Statement A spherical shell of inner radius a and outer radius b contains a uniform charge density ρ of total charge Q. (a) Find ρ (b) find the electric field for r< a, a< r< b, b< r sketch it Homework Equations E = kQ/r2 V=4πr3 The Attempt at a Solution ρ π...
  9. A

    Transport phenomena - shell balance

    Homework Statement Use a shell balance method to derive the equation governing the two dimensional temperature distribution,u, in a circular disk in polar coordinate system(r,theta). allow for the possibility of differing thermal conductivities in the r and theta directions. Homework...
  10. D

    Conducting spherical shell with point charge

    Hi, I received this question on my exam today and it stumped me... Conducting spherical shell of inner radius 0.045m and outer radius 0.18m, which has a net charge of zero. A charge Q of 5.5x10-5 is placed at the center, find the electric fields at point A (0.03m), point B (0.06m), and...
  11. M

    Understanding Gauss' Shell Theorms?

    So there are two theorems: 1. A shell of uniform charge attracts or repels a charged particle that is outside the shell as if all the shell's charge were concentrated at its center. 2. If a charged particle is located inside a shell of uniform charge, there is no net electrostatic force on...
  12. A

    Dont understand the bounds of this integral, shell method.

    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=4x-x^{2} , y=4 , x=0 Homework Equations V=2\pi\int p(x)h(x) from a to b The Attempt at a Solution...
  13. P

    Electric Potential inside and outside a spherical Shell

    1. Find the electric potential inside and outside a uniformly charged sphere of radius R, and whose total charge is q. Use infinity as your reference point. Compute the gradient of V in each region and check that it yields the correct field. Sketch V(r). 2. I used the theorem that electric...
  14. L

    Calculate E inside a spherical shell

    Homework Statement Calculate the electric field, E, for general points inside a shell which has a radius R. It also has a uniform surface charge density, σ. First, do it with Gauss’s Law. Then find E more directly. Hint: Use Law of Cosines and a substitution. Homework Equations...
  15. T

    Moment of inertia of spherical shell

    Homework Statement Moment of inertia of spherical shell of radius R, mass M along its rotation axis is given by \frac{2}{3}MR^{2} I am trying to calculate thisHomework Equations The Attempt at a Solution This is my attempt but is unsuccessful, since the spherical shell is an assembly of rings...
  16. S

    Potential of Concentric Cylindrical Insulator and Conducting Shell

    Potential of Concentric Cylindrical Insulator and Conducting Shell...Please Help Homework Statement An infinitely long solid insulating cylinder of radius a = 3.6 cm is positioned with its symmetry axis along the z-axis as shown. The cylinder is uniformly charged with a charge density ρ =...
  17. C

    Shell Method Example: Finding Volume Using Shell Method

    Homework Statement The area between the y-axis and the line y = x + 1 from y = 2 to y = 4 is rotated about the x-axis. Use the shell method to find the area of the resulting solid. Homework Equations V = 2pi integral (radius)(height of shell) dx or dy The Attempt at a...
  18. W

    Line Charge and Charged Cylindrical Shell

    Homework Statement 1. Homework Statement An infinite line of charge with linear density λ = 7.5 μC/m is positioned along the axis of a thick insulating shell of inner radius a = 2.9 cm and outer radius b = 4.9 cm. The insulating shell is uniformly charged with a volume density of ρ =...
  19. A

    What is the linear charge density of the insulating shell in this problem?

    Homework Statement An infinite line of charge with linear density λ = 7.5 μC/m is positioned along the axis of a thick insulating shell of inner radius a = 2.9 cm and outer radius b = 4.9 cm. The insulating shell is uniformly charged with a volume density of ρ = -612 μC/m3. What is λ2...
  20. Terocamo

    Charged shpere inside grounded shell

    Homework Statement There is a Charged metal sphere with radius b placed inside the central of a ground metallic shell with a radius a. What will be the work done in bring a small positive charge q from infinity to the surface of the inner sphere? Homework Equations...
  21. Z

    Charge inside a spherical conducting shell

    If a charge is placed inside a spherical conducting shell, is the total electric field inside it zero? I am thinking that if the charge is positive, then the conducting shell will have an equal amount of negative charge on its inner surface, therefore the E field should be zero inside, right?
  22. P

    Potential inside a hemispherical shell

    i have a hemispherical shell with a radius of R ,and which has V=V0 potential on it. the main problem is i have to find the potential inside the shell for every (r,\theta,\phi) points. 1. I think the potential will depent on only the distance from origin, there won't be any \theta or \phi...
  23. nomadreid

    Virtual shell around a charged particle?

    In quantum renormalization, one distinguishes between the (unobservable) bare electron and the observable properties. The justifications that I can find for the procedure seem to rest purely on mathematical and empirical grounds: the methods are in line with a consistent mathematical theory...
  24. M

    1D three-body problem (with spherical shell)

    Let's suppose that we have two point particles with masses m1,m2 and the spherical shell with mass M, placed in a line, at distances h1,h2 and H from 0 in that line (0 is the center of some inertial frame of reference). The initial conditions and the equations of motion are the following...
  25. M

    1D three-body problem (with spherical shell)

    Let's suppose that we have two point particles with masses m1,m2 and the spherical shell with mass M, placed in a line, at distances h1,h2 and H from 0 in that line (0 is the center of some inertial frame of reference). The initial conditions and the equations of motion are the following...
  26. M

    Minkowski-minkowski thin shell paradoxon?

    Spherically symmetric infinitesimally thin shells can be described via the well known junction formalism of Israel. Let us consider such shell in vacuum, this means that on both sides of the shell we have Schwarzschild spacetimes. One of the dynamical equations is the first component of the...
  27. M

    Can we use the Schwarzschild metric under the horizon?

    Hi everybody, The framework of infitesimally thin shells is the well known Israel junction formalism. Let us suppose motion of a thin in Schwarzschild spacetime. I mean both side of the shell is desribed by Schwarzschild metric. Let us suppose that the shell consists non-massless...
  28. M

    Thin shell velocity is greater than speed of light?

    Spherically symmetric infinitesimally thin shells can be described via the well known junction formalism of Israel. The equation of motion of thin shells is (G=c=1): (dr/dtau)^2 = (mg/mr)^2 - 1 + (2mc+mg)/r + (mr/2r)^2 This is an energy balance equation, where r is the...
  29. P

    Shell Side Fluid Velocity of Baffled HX & Re - Nobody knows last resort

    Shell Side Fluid Velocity of Baffled HX & Re -- Nobody knows last resort Problem: I need to know how to calculate the shell side fluid velocity for a Shell&Tube HX with *Baffles*. Also, the reynolds number for this flow Known: ms -Mass flow on shell side Nt -Number of tubes Lt -Length of...
  30. M

    Shell and Tube Exchangers: What You Need to Know?

    hello guyz i have some questions about shell and tube exchangers 1- what's the difference between shell and tube exchanger over the plate exchanger ?? 2- what's the data required for selecting heat exchanger ?? 3- if i will replace the shell and tube with a plate exchanger what's the...
  31. W

    Spherical Shell in External Field

    Homework Statement An uncharged hollow conducting spherical shell with inner and outer radii a,b respectively is placed into otherwise uniform electric field E. Calculate the induced charge density at a and b and electric field everywhere Solution for E ,r>b E = E_0...
  32. R

    Exploring Nuclear Energy Levels: Shell Model

    I am trying to explain nuclear energy levels in terms of Shell model and I hope that you guys would assist me through this- 1. The potential which exists inside the nucleus is assumed to be harmonic oscillator potential and it's value is obviously given by V(r)=\frac{1}{2}m\omega ^2r^2 However...
  33. F

    Collapsing and expanding shell theorem

    I've been philosophing about Newtons shell theorem, which tell us that inside a symmetrical sphere, gravity is zero if the sphere is hollow, and linearly declining while moving closer to the center if the sphere is massive and of constant density. Now, if the sphere was hollow it would...
  34. E

    Shell Model: Filling g9/2 Shell w/ 5 Protons

    Homework Statement How do 5 protons fill a g9/2 shell in the shell model? There are 10 spots in the g9/2 shell. Homework Equations The Attempt at a Solution Pauli principle dictates the first four to be in anti-parallel pairs. But the last can be either up or down. Am I missing...
  35. B

    How to Calculate Self Inductance in a Toroidal Shell Coil?

    I've got the probem with determination the formula of inductance in the toroidal coil. This coil has a shape of toroidal shell (like one torus inside the second). 1 torus: (x-R0)^2-y^2=r1^2 2 torus: (x-R0)^2-y^2=r2^2 The shell is a magnetic material with given permeability "ur". The...
  36. I

    Capacitance and inductance of cylindrical shell

    i am having trouble with finding inductance and capacitance of a cylindrical shell with gap. say inner radius is a, outer radius is b, and filling dielectric between a and b, and its not a exact circle which have a small gap say d. its like a split ring but only one shell. How can i...
  37. J

    Newtonian mechanics & Oort Cloud Shell

    Last week there was a documentary program on Nat Geo I believe having to do with the composition and origins of comets. The narrative seemed to imply that comets originate within & are rather randomly dislodged from a spherical shell around the Solar System called the Oort cloud. This...
  38. K

    Exploring Gauss' Law: Induction by Charges Outside a Shell

    Homework Statement http://img685.imageshack.us/img685/9501/10953060.png" Homework Equations The Attempt at a Solution I know you use Gauss' Law, but why wouldn't the charges outside of the shell induce a charge on the shell, which would then affect the field at P?
  39. S

    Sphere in a spherical shell

    Suppose a solid insulating sphere of radius a carries a net positive charge uniformly distributed throughout its volume. A conducting spherical shell of inner radius b and outer radius c is concentric with the solid sphere. Determine the induced charge per unit area on the outer surface of the...
  40. R

    Insulating Spherical Shell Potential Problem question

    Homework Statement I have a question about an upper-division E&M HW problem I'm stuck on. Any help would be GREATLY APPRECIATED! Problem Statement: An insulating spherical shell of radius R was set up to have a potential on its surface of V=A*cos^2(theta), where A is a constant...
  41. W

    The electric field inside a shell with a charge at the center?

    Hello. I am preparing for the AP Physics C E&M exam, and I am trying to understand the solution to 2004-1 The problem provides an infinite line of uniform charge per unit length enclosed within an infinite hollow conducting cylinder with a fixed radius and no net charge. The line of charge...
  42. M

    Problem Deriving Volume of a Cylindrical shell

    I have seen the derivation for the formula: h2(pi)rdr used in math textbooks. However, earlier today I had a physics problem where I needed to use the volume of a cylindrical shell of inner radius r and outer radius dr+r and length h. without remembering the formula I tried to derive it...
  43. FeDeX_LaTeX

    How Do Electron Shell Capacities Determine Chemical Formulas?

    Hello; I couldn't find the answer to this anywhere, so I thought that I might ask here instead. What are the electron shell capacities for any given element? I think that any elements that are arranged in GROUPS have electron capacities that follow the pattern; 2,8,8,18,18,32,32... is this...
  44. J

    Shell Nitrogen Enriched Gasoline

    How does this clean your engine's valves, like the commercials show? Wouldn't it just increase the cars NOx emissions? Thanks
  45. S

    Distorted orbital shell when E-field applied (Dielectrics)

    Homework Statement Єr = 3.0, atomic density = 1028 atoms/m3. The mag. of the E-field is 10,000 [V/m]. Two electrons in outer orbital shell will distort with an applied E-field. If both both electrons follow some orbital path as a pair, find spacing between center of nucleus and average...
  46. T

    Number of protons and neutrons per shell?

    before i start i wanted to make it clear that this is NOT homework. its just a quick question which puzzled me and my friend In the shell model of the nucleus. i found a statement that said that since both neutrons and protons are fermions, there are restricted to 2 of each at each energy...
  47. T

    Spherical shell rolls down a ramp with friction-time?

    spherical shell rolls down a ramp with friction--time? Homework Statement A 120 g basketball has a 25.7 cm diameter and may be approximated as a thin spherical shell. Starting from rest, how long will it take a basketball to roll without slipping 6.29 m down an incline that makes an angle of...
  48. S

    Is the space between the electron shell and nucleus a perfect vacuum?

    Is the space between the electron shell and nucleus a perfect vacuum?
  49. S

    Understanding Charge Distribution in a Spherical Shell

    Homework Statement I have a simple question. There is positive point charge in the center of a sphere 2.5 micro c. The spherical shell has inner radius of 60 cm and outer radius of 90 cm. The net charge of the spherical shell is equal to zero. Homework Equations The...
  50. E

    Shell thickness of a pressure vessel required subjected to a cyclic pressure

    I was wondering if anyone could help me with the following question, please: A thin walled pressure vessel is to be used as a pressure accumulator in a number of situations all involving a number of different operation conditions some of which create cyclic stresses. The dimentions of the...
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