What is Cable: Definition and 628 Discussions

A cable layer or cable ship is a deep-sea vessel designed and used to lay underwater cables for telecommunications, electric power transmission, military, or other purposes. Cable ships are distinguished by large cable sheaves for guiding cable over bow or stern or both. Bow sheaves, some very large, were characteristic of all cable ships in the past, but newer ships are tending toward having stern sheaves only, as seen in the photo of CS Cable Innovator at the Port of Astoria on this page. The names of cable ships are often preceded by "C.S." as in CS Long Lines.The first transatlantic telegraph cable was laid by cable layers in 1857–58. It briefly enabled telecommunication between Europe and North America before misuse resulted in failure of the line. In 1866 the SS Great Eastern successfully laid two transatlantic cables, securing future communication between the continents.

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  1. breadvsrice

    Vertical Cable, Torque, Force applied to Wheels

    I am working on a project at my University. It's extra-curricular and not homework related. At the end we will give a report on what we learned during the development. Our team is working on some ideas for a basic robotic climber, that climbs a cable (similar to a seatbelt). What we decided...
  2. tipu_sultan

    What is the meaning in the 144 Optical Fiber Cable? Especially why 144

    During studying the telecom underground cable network I came across the Optical Fiber Cable having the 144 fibers (single mode). I want to know why 144? Is this a Some standard to have 144 fibers in one cable? I have also viewed some of the datasheet having 144 fibers Optical Fiber Cable...
  3. A

    How Many Panels Need to Be Lifted for Security Cable Installation?

    A door company makes doors out of square wooden panels. After installing many doors, they are asked to install a security cable that runs diagonally from the top right to the bottom left. With an n*m door, how many panels need to be lifted to place the security cable? So what I did at first...
  4. I

    Empty elevator with a max speed going down, find tension on cable.

    My apologies for asking two questions in a short period of time, this is the last question I have. Hopefully one day I'll be skilled enough to answer everyone elses! :) Homework Statement An empty elevator has a mass of 722 kg. It moves between floors at a maximum speed of 6.00 m/s. The...
  5. L

    Flux density inside and outside a coaxial cable.

    For question 4b in the problem sheet attached below, is my working correct for B outside and inside the coaxial cable? Ans: Outside coaxial:∫B.dl = μI (the integral is between 0 and 2∏r) => B = (μI)/(2∏r) Inside the coaxial: \int_{2\pi a}^{2\pi r} B.dI = μI.\frac{a^2}{\pi...
  6. U

    What is the inductance of a length l of a coaxial cable?

    A coaxial cable is modeled as a long thin cylindrical shell with radius b concentric with a solid wire of radius a (the wire is inside the shell). Calculate the inductance of a length l of this cable. (Example 32.5 Here) ---> https://echsphysics.wikispaces.com/file/view/APPhysicsCH32.pdf...
  7. N

    Calculate Coaxial Cable Loss & Input Impedance at 1 MHz

    Hey Guys, How do I work out Transmission loses and input impedance for coaxial cable? I’ve been given this website to use http://fermi.la.asu.edu/w9cf/tran/ I do have the characteristic impedance of 75Ω and frequency and I am asked to work the attenuation in dB/100ft and “input...
  8. H

    Cable trays: Return Flange cable tray

    I am designing cable tray for installation, while i am looking on different types of cables trays i found that there is cable trays called "Cable trays with return flange". So i am wondering where such type of trays is used? Thanks, Hisham
  9. M

    A 1130-kg car is held in place by a light cable on a frictionless ramp

    Homework Statement A 1130-kg car is held in place by a light cable on a very smooth (frictionless) ramp. The cable makes an angle of 31.0° above the surface of the ramp, and the ramp itself rises at 25.0° above the horizontal. a). Find the tension in the cable. b). How hard does...
  10. K

    Suspending Cable under own weight

    Homework Statement In this project, the methodology of Finite Elements and convergence of numerical solution is explored. A cable has the following properties: weight per unit length of wo = 5 N /m length l= 24.2m The cable is suspended with its two ends a distance of L = 20 m...
  11. A

    Tensions of cable over a pulley

    In the figure attached, we have one section which has three bars all pin-connected together and pin fixed on the ground. We have two pulleys connected with the section by string. And we have one string starting from the left fixed pin to the right fixed pin. I am thinking whether the tension...
  12. K

    Find the tension in the horizontal cable that supports the boom

    Homework Statement A crane in a marble quarry is mounted on the rock walls of the quarry and is supporting a 2000 kg slab of marble as shown in the figure. The center of mass of the 900 kg boom is located one-third of the way from the pivot end of its 15-m length, as shown. Given...
  13. R

    Resistance of the insulation in coaxial cable

    Homework Statement Determine the resistance of the insulation in a length l of coaxial cable.inner radius = a and outer radius= b.Homework Equations R=\rho\frac{l}{A} Area= \pi (b^2 - a^2) The Attempt at a Solution I calculated the area between the two concentric 'circle' with radius 'a'...
  14. P

    Breaker with Over-Sized Cable

    I'm familiar with the smallest breaker/ cable requirements for a load. Example, a 10A continuous load would require a 10A * 1.25 = 12.5A rated breaker or "the next standard size up". Unfortunately, "the next standard size up" is ambiguous and I'm wondering how large a breaker/cable can be for...
  15. M

    Tension in cable and reaction force

    Homework Statement Homework Equations The Attempt at a Solution For this problem, what I am confused about is the fact that the Z direction parts of the tension will tend to rotate in a direction different from the Y components of the tension and the 850 lb vertical force. I am not sure how to...
  16. M

    Newtons Laws, Finding tension in the tow cable and foce

    Homework Statement Just started tension problems and having some trouble figuring out how to approach the problem. Thanks for any help in advance. Consider a rocket that is taking off and towing a large container of trash. The rocket’s engines exert a force, F, that causes the rocket and...
  17. S

    Statics cable length problem

    Homework Statement The window is held open by the cable AB. Determine the length of the cable and express the 30N acting at A along the cable as a Cartesian vector. http://img802.imageshack.us/img802/9599/ru5y.jpg Homework Equations vector(F) = FuAB The Attempt at a Solution Here's my...
  18. 2

    Need Help Finding a Cable Quick Connector

    Can someone suggest a product or point me in the right direction of something that will do the following. I have a 24V DC LED panel connected to a dimmer by a cable that has 4 conductors with a 24 AWG size. I need to put a quick connect between the dimmer and the LED panel. The smaller this...
  19. W

    Coaxial Cable Problem - Finding volume charge density.

    1. Homework Statement A long coaxial cable consists of an inner solid cylinder, radius a, and an outer thin coaxial cylindrical shell, radius b. The outer shell carries a uniform surface charge density σ. Find the uniform volume charge density ρ that the inner cylinder must have in order...
  20. PsychonautQQ

    Why do two opposing currents cancel each other out perfectly in Ampere's Law?

    Homework Statement http://grephysics.net/ans/9277/9 I'm confused why these two currents cancel each other out perfectly when the distance they are being measured from is closer to the outside current than the inside current... Like if the magnetic induction is proportional to the...
  21. R

    Testing Book for Coaxial cable problem in Physics GRE

    Book for Coaxial cable impedance problem in Physics GRE This is GR9277, Problem 18. Is this covered in any physics undergraduate course? What subject is this problem belong to? What book do you recommend for studying this? How can I make the picture appear bigger?
  22. G

    How Do Fiber Optic and Copper Cables Differ in Physics?

    Hey I am about to start a research paper on the physics concepts involved in relation to fibre optic cabling and copper cabling. In my report I have to discuss how the physics in both relate and differ from one another. In terms of fibre optic cabling I have decided to talk about snell's law...
  23. D

    Work problem on winding up a cable

    Find the work done in winding up a 300ft cable that weighs 2.00 lb /ft W=Fd W=$$\int F dx$$ My attempt w=F*D so W= (300ft)(2.00lb/ft) W=600ft.lb and $$\int_0^{300}\!\ 2xdx$$ W=90,000 ft.lb I'm taking Calc 2 and this is applied Physics problems...
  24. J

    Effects on a cable at sea level compared to 35,000 feet

    Hi Guys, Struggling to find any information on the changes to a cable at altitude compared to at sea level. The initial task was to calculate the resistance of generator wires and then change them from copper to aluminium cables to save weight. I have done this leading me onto describing the...
  25. A

    Total internal reflection inside a fiber optic cable

    Homework Statement A multi-mode fiber optic cable has a core diameter d = 115 mm, ncore = 1.42, and ncladding = 1.17. What is the largest possible angle θin relative to the surface normal that light can enter the fiber (i.e. pass from air into the fiber core) and experience total internal...
  26. Gliese123

    Formula/calculation of the magnetic field & inductance in a AC cable

    Hello dear PF-members! :shy: I'm looking for some appropriate formula which could be utilized to calculate the magnetic field density in a straight high voltage AC mere cable. If you're more into the details of why I may ask this - I'm working with the railway maintenance and got interested in...
  27. Y

    What is the tension in the cable and the reaction at D?

    Homework Statement A force P of magnitude 90 lb is applied to member ACE, which is supported by a frictionless pin at D and by the cable ABE. Since the cable passes over a small pulley at B, the tension may be assumed to be the same in portions AB and BE of the cable. For the case when a = 3...
  28. D

    Solving Tension in a Cable Homework

    Homework Statement Im having trouble understanding how to find the tension 'T' and pretty much answering the question on the .jpg file i have attached Homework Equations ƩFx=0, ƩFy=0, τ=r x F The Attempt at a Solution For question 17 i have: TLsinθ - w(l/2cosθ)-w(Lcosθ)= 0...
  29. C

    Overhead electrical transmission cable sag questions

    These are questions for electrical engineers involved in electrical power transmission by overhead line and knowledgeable about current practices. - What catenary sag is normal, under normal conditions of weather and transmitted current? [obviously the answer will depend on the distance...
  30. A

    Mutual inductance between straight line cable & square shape Frame

    Homework Statement Calculate mutual-inductance between straight line cable and square shape frame, as shown on picture. Homework Equations I am not sure which equation will be used here because as far as my knowledge goes , mutual inductance should be concerned with turns in...
  31. T

    Calculating the appropriate cable strength.

    5 years ago I was at penn state, for engineering of all things. I did things similar to this but everything is eluding me at the moment. My situation: I have a car that I've attached a class 1 trailer hitch. Its rated at 2000lbs and i don't intend on towing more than 1000 lbs. For a...
  32. A

    Inductance of Solenoid on Coaxial Cable

    Homework Statement The figure below shows a short coil which is coaxial with a very long solenoid (you may approximate it as infinite.) Coil: Has 120 turns of radius 1.8 cm and resistance 5.8 . It is not attached to anything. Solenoid: Has 22700 turns/m and a radius of 1.6 cm. It receives an...
  33. I

    Calculating Fluid Dynamic Forces on a Towing Cable

    I am trying to develop a calculator to approximate the depth of a trolling rig used by fisherman, which is typically a lead weight with a hook (jighead), attached to a single plastic/rubber shad body (http://www.tacklecoveshop.com/images/Product/icon/1734.jpg). The other typical rig is a...
  34. S

    I don't know how to find tension in a cable

    I don't know hwo to find tension in a cable with two angles in the diagram. I have a car that weighs 1130kg held in place with a cable on a ramp that forms an angle of 25° above horizontal and the cable makes an angle of 31° above the surface of the ramp. I have to find the tension in the...
  35. K

    Temporarily powering 5.5v board from 2.5v ethernet cable

    I'm not an EE. I'm a Software Engineer. I would like to build a small circuit that would leach power from an active 2.5v Ethernet line to charge a capacitor very slowly (over a timespan of 1-2 minutes). When the capacitor is fully charged, it would then discharge at 5.5v to power a circuit...
  36. K

    Determining smallest possible diameter of a cable

    Homework Statement You have a round steel cable with diameter d and a ultimate strenght of 400Mpa. There is a force of 8,2KN working along the cable. What is the smallest possible diameter the cable can have without breaking? Homework Equations δ= N/A Area of a circle: πr^2 The...
  37. P

    Cable segment and repeater spacing.

    Hi, I've read that the max length of UTP and STP cable segments is 100m? Does this mean that a repeater is required after every signle cable segment?
  38. J

    How does a single fiber optic cable transmit millions of signals

    That's how the internet works across oceans, correct? I understand how a fiber optic cable transmits information, but how does it transmit everybody's information at once in just one dollar coin sized cable? One after the other? I find that hard to believe given how fast the internet is, even at...
  39. G

    Calculating Cable Resistance for Internal Temperature

    Hi. I am a bit confused about the formula for cable resistance. It is quite a long question but I got stuck at this point. I have found the resistance Rdc@20 degrees but I need to adjust it for "internal working temp" of 60 degrees. The formula I have found gives compensation for changes in...
  40. S

    MHB Find Distance between Poles Given Hanging Cable

    The ends of an 80-foot cable are attached to the tops of two 50-foot pole. The lowest point of the cable is 10 feet from the ground. Find the distance between the poles. L = 80 * * | | | | |*...
  41. E

    Magnetic field of a Coaxial Cable

    Homework Statement A long coaxial cable consists of two concentric conductors with dimensions a = 1.20 cm, b = 5.40 cm and c = 7.30 cm. There are equal and opposite currents of 5.00 A in the conductors. Find the magnitude of the magnetic field at a distance of 0.36 cm from the center axis...
  42. G

    Archived Coaxial Cable With Potential Difference between conductors

    1. A coaxial cable is powering a light bulb with a steady flow of current (DC current). The electric potential difference between the outer and the inner conductor of the cable is delta V and the current flowing in the cable is I. The inner conductor's outer radius is a and the outer conductor's...
  43. C

    Find the tension in each cable

    Homework Statement A lamp has a mass of 18.5 kg and is suspended by two cables attached to the ceiling. The cable on the right makes an angle of 42.2° with the ceiling and the cable on the left makes an angle of 54.4° with the ceiling. Find the tension in each cable? Why is the sum of the...
  44. A

    Tension in a cable supporting a hinged beam

    I have tried to complete the following question by taking moments about point A, but to no avail. Could anybody help me with where i am going wrong. Do I need to include perpendicular distance? The I-beam A-B shown below is supported by a cable at B and a pin at A. The cable is inclined at an...
  45. A

    Calculating the force required to displace a tensioned cable

    Hi, I'm trying to figure out a method for calculating the force required to displace (axially by 5mm) an elastic material that is tensioned longitudinally at 105 N. Material properties: Cross-sectional area: 100mm^2 Stiffness, K = 1652 N/mm Modulus, E = 0.68 GPa Length of material...
  46. A

    Difficult optimal cable cost analysis

    Homework Statement http://snag.gy/z4LzZ.jpg I was going through some old course work from when I was an undergrad and was unable to complete this one. If you could just provide me with the proper approach/steps it would be much appreciated. I know how to solve all of the tensions, but...
  47. F

    Impedance matching joint between cable and ground

    I would like to impedance match a few joints in a circuit and would appreciate some thoughts about this, since I would like the match to be as perfect as possible. The problem is complicated by the fact that the available equipment only consists of trimpot(s). The joints are mostly cables to...
  48. G

    A Uniform Beam Supported by a Cable

    Homework Statement A uniform 250 kg beam is supported by a cable connected to the ceiling, as shown in the figure. The lower end of the beam rests on a rough, horizontal floor. What is the magnitude of the tension in this cable? Image of the problem...
  49. G

    Cable technology question (audio quality)

    hi, first post here if this is too long to parse please skip to the actual question in bold, at the end :) I wasn't able to find any other concise title for this. maybe some of you are aware of the fact that in audio some give great importance to cable selection. for some the audible...
  50. S

    Control cable failure and critical flutter speed margin?

    Hi everyone here! I'm a LSA and PPL pilot, working on my CPL, and I have some questions to those who have knowledge of the aeroelastic effects and flutter phenomenon. I would like to talk a little about aerodynamic flutter onset speed and flight control malfunction. It is known that freeplay...
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