Resistance Definition and 1000 Threads

The French Resistance (French: La Résistance) was a collection of French movements that fought against the Nazi German occupation of France and the collaborationist Vichy régime during the Second World War. Resistance cells were small groups of armed men and women (called the Maquis in rural areas) who, in addition to their guerrilla warfare activities, were also publishers of underground newspapers, providers of first-hand intelligence information, and maintainers of escape networks that helped Allied soldiers and airmen trapped behind enemy lines. The Resistance's men and women came from all economic levels and political leanings of French society, including émigrés, academics, students, aristocrats, conservative Roman Catholics (including priests and nuns), Protestants, Jews, Muslims, liberals, anarchists, and communists.
The French Resistance played a significant role in facilitating the Allies' rapid advance through France following the invasion of Normandy on 6 June 1944. The French Resistance provided military intelligence on the German defences known as the Atlantic Wall and on Wehrmacht deployments and orders of battle for the lesser-known invasion of Provence on 15 August. The Resistance also planned, coordinated, and executed sabotage acts on the Nazi electrical power grid, transport facilities, and telecommunications networks. The Resistance's work was politically and morally important to France both during the German occupation and decades that followed. It provided the country with an inspiring example of the patriotic fulfilment of a national imperative countering an existential threat to French nationhood. The actions of the Resistance stood in marked contrast to the collaborationism of the Vichy régime.After the Allied landings in Normandy and Provence, the paramilitary components of the Resistance were organized more formally, into a hierarchy of operational units known, collectively, as the French Forces of the Interior (FFI). Estimated at 100,000 fighters in June 1944, the FFI grew rapidly and reached approximately 400,000 by October. Although the amalgamation of the FFI was, in some cases, fraught with political difficulties, it was ultimately successful, and it allowed France to rebuild the fourth-largest army in the European theatre (1.2 million men) by VE Day in May 1945.

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  1. H

    A Metal or Insulator: Examining Resistance in Multiple Directions

    Generally, a material is metal or insulator is simply determined by the gap. But if we view it in another way, to measure the resistance in different direction, says x and y, and there are usually different. And then measure the resistance change with temperature. Usually, the resistances goes...
  2. K

    Understanding Resistance: Exploring the Limits of Wire and Hose Capacity

    If you have wire that has 100 ampere current but your load is only 0.5 ampere.. how come the load won't be destroyed by the powerful 100 ampere source? Or let's take the case of hose. If you have water running so fast inside a 10 inches diameter hose.. and you put a small hose between it.. the...
  3. G

    Explaining a signal converting circuit

    i have a drawing of a circuit that converts a signal in range [-5,5] V to a range [0,1.2]V . i wish to understand how it works.. i have basic knowledge of electricity as an undergraduate in general physics but a bit rusty , thus i am here looking for answers...
  4. A

    Resistance of a non-ohmic device from its I/V graph

    What is the resistance of Device Q when a current of 200mA flows through it? Wouldn't the resistance of the device be approaching 0 Ω as its characteristic resembles one of a diode (gradient = 1/R)? Apparently, the answer is just using V = I R, and solving for the resistance. Is there...
  5. M

    I can't figure out what resistance values to use....

    I started an electronics program recently and I am a month into it so I am quite new at this. I have a problem involving a potentiometer and I don't understand how to compute the voltages because I don't know what I am supposed to use for my resistance values. I know that in series the total...
  6. E

    Voltage drop in the internal resistance of a voltage source

    In this circuit,first there will be voltage drop in the internal resistance of the voltage source.Mostly,the voltage source is assumed ideal in circuits,however,here a practical voltage source is assumed. So,there will be voltage drop in the internal resistance of the voltage source which will...
  7. M

    How to determine the change of resistance from I-V graph?

    1. Homework Statement How to determine the change of R of a non-ohmic conductor from different parts of I-V graph? Please see the sketch attached. Homework Equations R=V/I The Attempt at a Solution For the part that passes through the origin, it is obvious that the...
  8. Souhardya Nandi

    Can we calculate the rolling resistance coefficient theoretically?

    I was wondering that if rolling resistance is basically caused by slight deformation of a body, we must have formulas in place to relate it to the physical and material properties of a body. But when I went ravaging for it in library or internet, everything was experimental. I wished to know...
  9. J

    A 2-d and 3-d model for contact resistance of M/n-Si (book?)

    Hi, We're studying Contact resistance and the professor has given assignments on contact resistance. But I can't find any books to refer to. Here is one sample question: The books I'm referring to are ones by Donald Neaman, SMZ, Kanos. but none of them have any mention of 1-d or 2-d model for...
  10. Islam Sabry

    The equivalent resistance for the resistors in this circuit?

    Homework Statement If the circuit of parallel and series resistors , is as follows , what's the equivalent resistance for the group? Homework Equations neglecting the battery internal resistance... irrelevant to the question. The Attempt at a Solution I tried to do the following R1=8+12=20...
  11. S

    Air resistance in projectile motion

    In lower-division physics classes, air resistance is usually ignored to make the mathematics of projectile motion easier to understand. When air resistance is included, it's often stated that at lower velocities, air resistance is proportional to the velocity of the object, Fair ∝ kv At...
  12. C

    Air resistance - freefall and horizontal projectile motion

    We have two identical balls sitting at the same height. One of them is released without applying any force (it falls freely) and the other one is given a non-zero horizontal velocity. Which of them will hit the ground first? The force of air resistance is proportional to the square of the...
  13. Mzzed

    Calculating Q-Factor and Resistance for Series LC Filters

    I am trying to calculate the correct component values to use in a simple series LC filter, however I am not sure which value of resistance is to be included in these equations. When talking about a series LC filter, is the resistance required for calculating q factor the resistance of the...
  14. A

    I''What is the optimal resistance for maximizing battery terminal voltage?

    Homework Statement A battery has an emf of V and an internal resistance of r. What resistance R, when connected across the terminals of this battery, will cause the terminal voltage of the battery to be ? A. r= R B. R= 4r C. R= r/4 Homework Equations V=IRThe Attempt at a Solution Req= r+R =...
  15. S

    Why is the Thevenin resistance in this problem 3.2 kΩ?

    Homework Statement The problem and its solution are attached. Homework Equations "Steps to follow for Thevenin’s Theorem: (1) Find the Thevenin source voltage by removing the load resistor from the original circuit and calculating voltage across the open connection points where the load...
  16. Delta2

    Ohmic Resistance and Logic gates

    Is ohmic resistance a "necessary evil" in order for transistors to be able to function as logic gates? I mean, I have seen some circuits for the NAND gate in RTL and TTL and they both seem to involve ohmic resistances. Can we make a super conducting NAND gate that will have total ohmic...
  17. E

    Was there a mistake in our final exam question about resistance?

    Homework Statement This graph was given, which describes the current through a resistor, as a function of the voltage. Then, we were supposed to find the resistance of the resistor when 3V<V<5V. But it changes throughout this range, doesn't it? Because in the answers (Mind you, this is the...
  18. E

    Combined resistance in this circuit

    Homework Statement Find the combined resistance once the switch is closed. Homework Equations V=IR The Attempt at a Solution I tried applying Kirchoff’s law but I got many equations, I am sure there is a more efficient way. I also tried to re-draw the circuit, but wasn't sure how to do so...
  19. thee qs

    Find the resistance and EMF in a circuit

    Homework Statement translation ; we know the values of R1 = 1 ohm R2= 2 ohm R3= 6 ohm R4= 2 ohm R5= 4 ohm R6= 4 ohm we can also see the voltmeter reading a potential difference value of 8 volts , and the...
  20. David Koufos

    Air resistance differential equation

    Hello all, I want to say thank you in advance for any and all advice on my question. My classical mechanics textbook (Marion Thornton) has been taking me through motion for a particle with retarding forces. The example it keeps giving is: m dv/dt = -kmv which can be solved for: v = v0e-kt...
  21. E

    Comparing Resistance in PN Diodes

    Homework Statement I came across a question asking " which one of these circuits has the largest resistance to the current? Homework EquationsThe Attempt at a Solution * In A the positive terminal of the battery is connected to the p-type region and the negative one to the n-type region...
  22. C

    I Integration - Projectile Motion w/ Air Resistance

    I"ve seen several texts that say something like this: Our equation of motion along x is dvx/dt = -g(vx/vt) Integrating this, we obtain equation 178 at this link (pretty near the top; sorry, but I can't figure out how to put the equation here). It's from FitzPatrick's online notes for...
  23. Cheesycheese213

    Is there a relationship between voltage and resistance?

    I was getting a bit confused with Ohm's law, and the relationship between the current, resistance and voltage/potential difference? From my understanding, current and voltage both increase or decrease together, while current and resistance do the opposite? I was then wondering if there was any...
  24. Mohammad Hunter

    Electromagnetic coil and capacitors vs resistance

    I'm not really sure if this is even scientific but while calculating how much energy is stored in electromagnetic coils and capacitors, pretty much the same formula is used: For electromagnetic coils it's U=0.5LI2 For capacitors it's U=0.5CV2 Why I think they're the same is that in a sense L to...
  25. J

    What is the Resistance of the Patient in a Defibrillation Shock?

    Homework Statement When the defibrillation shock is applied, the capacitor discharges through the patient as shown in the diagram below: The fraction of charge remaining on the capacitor 1.00 ms after it begins discharging is 0.300. Calculate the resistance of the patient. Note: This will...
  26. Gabriele99

    Will water flow ever stop if we increase resistance?

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  27. S

    I finding the Thevenin equivalent resistance

    Homework Statement https://imgur.com/a/XD3Km4t I'm trying to find the thevenin equivalent resistance across the opened terminals. Homework Equations I know you short circuit the voltage source and do simple circuit analysis, however I'm getting confused in determining what resistors are...
  28. J

    Air resistance: cylindrical rotor in stator with air gap

    Hello, I am currently doing research on the aerodynamic properties of a rotating cylinder in a cylindrical housing. The cylinder represents a rotor in a electric motor. The air gap between rotor and stator is about 0.5mm. I'm looking for a theoretical analysis and calculation on the...
  29. A

    Finding the Optimal Combination of Resistors for a Desired Total Resistance

    Homework Statement I'm asked to find a combination of resistors (parallel and/or series) that uses resistors of 25 Ω, 100 Ω, 50 Ω, and 50 Ω. They should add up to give a total resistance of 62.5 Ω. Homework Equations Req for parallel = 1/R1 + 1/R2 + ... Req for series = R1 + R2 + ... The...
  30. A

    Voltage, Current, and Resistance Calculations

    Homework Statement I'm asked to find the voltage, current, and resistance through each resistor in the given circuit. Homework Equations Req for parallel = 1/R1 + 1/R2 + ... Req for series = R1 + R2 + ... The Attempt at a Solution First, I want to find the total resistance in the circuit...
  31. F

    Find the new resistance if its length and D are doubled

    Homework Statement Homework Equations ρl = RA A = π r2 The Attempt at a Solution l = RA (ρ is constant) A1 = π (D/2)2 = (πD2)/4 A2 =π (2D/2)2 = πD2 = A1 /4 l2 = 2*l1 ##R=\frac{l}{A}## R2 = (2l1)/(A1/4) = 8 l /A = 8R1 Could someone tell me where is my mistake ?
  32. D

    Calculating current with and without internal resistance

    Homework Statement Calculate the magnitudes and directions of the currents in each of the 3 resistors in the circuit above, if... (a) ...both batteries have zero internal resistance. (b) ...each battery has an internal resistance of 1.0 Ω. Homework Equations I1 = I2 + I3 (Node Law)The...
  33. NYAME EPHRAIM

    Yenka simulator to build an RS flip-flop

    < Mentor Note -- thread moved to HH from the technical forums, so no HH Template is shown > a) Using the Yenka (or similar) simulator, you are required to build an RS flip-flop using 2 NAND gates, switches, LEDs and 330Ω resistors. Test the circuit and prove its correct operation against the...
  34. J

    Equivalent resistance between two points

    Homework Statement Homework EquationsThe Attempt at a Solution From symmetry , C and D are at the same potential . So , resistance between them can be removed . This leaves us with three parallel branches between A and B i.e 45 Ω || 45 Ω || 15Ω . The net resistance will be 9 Ω . But this...
  35. D

    Batteries in series, parallel, and internal resistance

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  36. T

    Negative Heat Sink thermal resistance

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  37. T

    Thermal Resistance between Chip to Gold Tin Solder

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  38. E

    Equivalent resistance of a circuit

    Homework Statement Consider the electric circuit shown in the figure. Assume that V = 13.7 V, R1 = R2 = R3 = R4 = R5 = 7.00 Ω. What is the equivalent resistance of the circuit? Homework Equations total voltage of a series circuit is the sum of the voltage of all the resistors total current of...
  39. S

    Resistance, current and current density

    Homework Statement A coaxial cable consists of a core cylindrical wire and a coaxial cylindrical shell, as illustrated in the Figure below. Consider a cable made of copper, which has resistivity of ρ=1.70×10−8Ω·m. Thecorewirehasaradiusof r =1.0mm. Theinnerradiusofthe 1 outer shell is r = 5.0...
  40. B

    Calculating Resistance of Coaxial Cable with Isolator

    Homework Statement Coaxial cable has radius a of copper core and radius b of copper shield. Between there is an isolator with specific resistance ζ. What is the resistance of this cable with length L between the core and the shield? Homework Equations First, I tried to solve this like this...
  41. Muhammad Danish

    Current Dividing in an Electrical Circuit

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  42. OldWorldBlues

    Why Use Voltage Dividers Instead of a Single Resistor?

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  43. Ekaekto

    Breakage resistance of a Polycarbonate plate with flowed through drill hole

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  44. S

    Calculating the conductivity of a solution of HCl and HAc

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  45. J

    Equivalent resistance between two points on a circuit

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  46. J

    Effective resistance between two points using symmetry

    Homework Statement Homework EquationsThe Attempt at a Solution I am trying to solve this question by symmetry .If I draw a line perpendicular to the line joining AB then points C and D are symmetric . Now I am unsure how to proceed further .
  47. GoodPost

    Short-circuited Resistance in Parallel with Reactance

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  48. Stephenk53

    Water resistance in a flashlight

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  49. J

    Effective resistance between two points problem

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  50. A

    Hot metal lid on cool surface has resistance when pulled up

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