Relation Definition and 1000 Threads

  1. O

    Relation of resistance to power dissipation

    Equation (p=i^2 * R) seems to suggest that the rate of increase of thermal energy in a resistor is reduced if the resistance is made less. "Eq" : p =v^2/R seems to suggest just the apposite . How do you reconcile this apparent paradox?
  2. A

    Amplitude and energy relation in optics

    Hi Guys I have a very simple and basic question. Assume interface of two dielectric mediums. If the t is transmition cofficient for electricfield from medium 1 to medium 2 with refractive indexs n1 and n2, what is the transmitivity of power from medium 1 to medium 2? I know it is...
  3. P

    What does the relation for temperature dE/dS=T mean physically?

    The only reason I can think of is: By defining S=k_b \log \Omega, it just works out; for an ideal gas as well as for other systems (that I can't come up with right now). \frac{dS}{dE}=\frac {1}{T(E,...)}\, states that temperature is a measure of the increase in entropy when some energy is...
  4. J

    Relation between kinetic energy and temperature

    Where does the 3/2 come from? \frac{1}{2} mv^2 = \frac{3}{2} kT
  5. O

    Relation between commutation and quantization

    relation between "commutation" and "quantization" Hi people; Over the several texts I have read, I got the impression that position-momentum commutation relations is the cause of "quantization" of the system. Or, they are somehow fundamentally related. The only relation I know of, is to...
  6. M

    Impulse vs Fnet relation to damage?

    what does more damage an object w/ a high acceleration or a greater momentum i was watching one of my favorite tv shows "Justified" and i started to wonder would a bullet moving at a greater acceleration hence greater force (F=ma) inflict more damage or would a bullet w/ a greater velocity...
  7. M

    Resistance in case of non Ohmic current voltage relation.

    A non Ohmic relation of current and voltage is I=α(exp(eV/kT)-1). Where α,K,T,e are constant. What will be the incremental resistance? My question is if it don't follow the Ohmic equation then how it possible to find the resistance?
  8. chisigma

    MHB Non linear recursive relation....

    From mathhelpforum.com... Hi. This is my first post here so I hope I've posted in the right place. My question concerns finding closed forms of nonlinear recurrence relations such as the following... $\displaystyle a_{n+1}= a^{2}_{n}-1\ ;\ a_{0}=a$ (1) This one is both nonlinear and...
  9. I

    Is the relation reflexive, symmetric, transitive

    Indicate which of the following relations on the given sets are reflexive on a given set, which are symmetric and which are transitive. {(x,y)\inZxZ: x+y=10} Tell me if I'm thinking about this correctly It is not reflexive because the only 5R5. It is symmetric because any xRy and yRx where...
  10. T

    How Can Equivalence Relations Determine Equal Classes?

    I am trying to prove this as I am practicing for a test but I am pretty much clueless on this problem: Prove that if ~ is an equivalence relation on a set s and [a] denotes the equivalence class of a in s under ~, then a ~ b if and only if [a] = [b]. If anyone can give me some points on...
  11. P

    The Mass cut - The relation between 44Ti and 56Ni in supenovae remnants

    Would it be possible if you would help me with a quick question, (as none of the staff here, or postgraduates can answer this question)? My group are designing a gamma ray telescope to look at nucleosynthesis in Supernovae. We have found a thing called the 'mass cut' (the separation between...
  12. G

    Max/Min in Calc III- Confused about relation between equations logic?

    So, I technically got this problem correct (our professor gave us the answers but not the total solution). My question is more of a logic one- an answer that I'll need to apply this concept to problems on the exam. I included it at the bottom of the post, after I explained the problem Find...
  13. fluidistic

    How Do You Derive P(V) for an Ideal Gas Transformation with dQ=0?

    Homework Statement Find the relation P=P(V) for a transformation dQ=0 in an ideal gas (PV=nRT and U=CnRT).Homework Equations dU=dQ-PdV.The Attempt at a Solution If I assume that C and R are constant I get dU=CR \left [ \frac{\partial (nT)}{\partial n} dn + \frac{\partial (nT)}{\partial T } dT...
  14. T

    Nonsensical (lack of) relation between area and arc-length of polar curves

    It is known that the area of a sector of a polar curve is \frac{1}{2}\int r^{2} d \theta This of course comes from the method of finding the area of an arc geometrically, by multiplying the area of the circle by the fraction we want \frac{\theta}{2\pi}\pi r^{2} Today I learned how...
  15. L

    Relation between Gamma and Poisson

    I'm having trouble doing a classic proof (integration par part and induction on r) for this : Pr(X>t)=Pr(Y ≤r−1), where X follows a gamma Γ(α = r, β = 1/λ) and Y a Poisson P (λt). Start with r = 1 (exponential distribution). I don't really understand what induction on r really means...
  16. T

    Equivalence of Subgroups in a Group

    Homework Statement Let H and K be subgroups of the group G. Let a,b \in G and define a relation on G by a ~ b if and only if a = hbk for some h \in H and k \in K. Prove that this is an equivalence relation.Homework Equations a = hbkThe Attempt at a Solution The goal is to prove the reflexive...
  17. F

    Distances to galaxies using the Hubble Relation: look-back time

    Hi all, this is my first post; apologies if it seems a bit basic, I suspect there's something fundamental I'm not getting here :smile: Say I observe the spectrum of a galaxy, and I calculate its redshift. I then use the Hubble Relation to find its distance, which is, say, ten billion light...
  18. A

    Combinatorial Proof of a Recurrence Relation

    So my professor gave us this recurrence relation to prove combinatorially for extra credit, but I was unable to figure it out. h(n) = 5h(n-1) - 6h(n-2) + 1 This was my solution, but I couldn't figure out how to factor in the +1: Let hn be the number of ways to arrange 0,1,2,3,4 on a 1xn...
  19. T

    Is There a Relationship Between Mass, Charge, and Energy in Our Universe?

    Hi All A question that bothering me and I can't find answer for: a charged particle in empty space will generate an electromagnetic field that has energy density and can be described by Energy-Momentum Tensor. A non charged particle at rest also has energy due to mass energy...
  20. M

    Uncertainty relation between number of photons in an EM field and its phase

    Derive the relation Δn.Δσ ≥ 1/2 where n is number of photons in an EM field and σ is phase Using heisenburgs uncetertainty principle? Tried subbing in frequency into heisenburgs uncertainty principle to get to the number of photons and to get rid of mometum is this the right line? Dont...
  21. Z

    How can I get a function relation with these two sets?

    Homework Statement I have these two sets: Pairwise, (1, 1) (2, 4) (3, 9) (4, 16). Clearly this is just squared. How can I get a function relation with like: (1, 1) (2, 3) (3, 9) (4, 10) or like (1, 1) (2, 5) (3, 12) (4, 22) Homework Equations The Attempt at a...
  22. L

    Combinatorics - Recurrence Relation Question

    Homework Statement For n ≥ 1, let g(n) be the number of ways to write n as the sum of the integers in a sequence of any length, where each integer in the sequence is at least 2. For n≥3, show that g(n) = g(n-1) + g(n-2).2. The attempt at a solution I've gone through values of g(n) for...
  23. F

    Relation between spontaneous emission, absorption and re-emission

    Hello Forum, when a wavefield is incident of an atom and the photon have the right energy (equal to the band gap energy), the photon is absorbed and disappear... But isn't the photon re-emitted later on and allowed to propagate through the material or does all its energy get lost into heat...
  24. D

    RElation of partial differential operator and Basis vector

    Hi everyone: How is the following derived? Just for example: \Deltax\alphae\alpha=\Deltax\alpha(\delta/\deltax\alpha) does it not mean? e\alpha=\delta/\deltax\alpha But How?
  25. N

    Proving Equivalence: Cos^2(x) + Sin^2(y) = 1

    Homework Statement The question is to show that Cos^2(x) + Sin^2(y) = 1 is an equivalence relation. The Attempt at a Solution I know that there are three conditions which the equation must satisfy. (reflexivity, symetry, transitivity) For reflexivity I tried: Cos^2(x) - Cos^2(x) = Sin^2(y)...
  26. T

    Questions in relation to the design of Rockets

    Hey everyone, I'm in the process of designing a rocket that could achieve high(er) altitudes. Of course, I want to make the rocket as small as possible, but maximize the height. I understand that the Mass fraction of the craft should be 0.91, where 91%~ is fuel/propellant, 6%~ is payload, and 3%...
  27. D

    Curent densitys relation to drift velocity

    Homework Statement A beam contains 4.0x10^8 doubly charged positive ions per cubic centimeter, all of which are moving north with a speed of 1.2x10^5 m/s. (a) What is the magnitude of the current density ? (b) What is its direction? (c) What additional quantity or quantities are needed...
  28. B

    Ordered Pairs in Relation A to B

    Homework Statement List the ordered pairs in the relation R from A = {1, 2, 3, 5} to B = {2, 4, 6, 9} where <x, y> is an element of R iff: (i) x ≥ y (ii) x – y < 2 (iii) x – y > 2 (iv) l.c.m. (x, y) = 18 (v) g.c.d. (x, y) = 3 I understand in general ordered pairs and...
  29. S

    Meaning of normal coordinates and normal modes, in relation to phonons

    I am trying to find a succinct definition of normal coordinates and normal modes - relating to numerous coupled harmonic oscillators. What exactly do the normal coordinates describe about these coupled harmonic oscillators? I know that for normal modes, all parts of the system move with...
  30. S

    Please show me how to simplify this recurrence relation

    I'm doing a much larger problem and I am stuck going from: T(n) = 14 + T (n − 2) + 10(n + (n − 1)) to T(n) = (n − 1)7 + T(1) + 10(Σi=2 to n of i) and I would very much appreciate it if someone could show me the detailed steps. (I've been told something about expanding the recursive...
  31. W

    Voltage/Current Relation That I Having Problems With

    I know I knew this many years ago and I am sure the answer is simple but I would really appreciate the help. Event That Brought Up The Question: Working on a complany vehicle, there was a heater fan that would keep failing. As we troubleshot, we saw that system voltage was low (bad...
  32. A

    Operators satisfying abstract commutation relation; then finding an eigenvalue.

    So, my problem statement is: Suppose that two operators P and Q satisfy the commutation relation [Q,P] = Q . Suppose that ψ is an eigenfunction of the operator P with eigenvalue p. Show that Qψ is also an eigenfunction of P, and find its eigenvalue. This shouldn't be too difficult, but...
  33. A

    Relation of Energy Fluxes of Two Objects

    Homework Statement Suppose two objects have energy fluxes, f and f + Δf, where Δf ≪ f. Derive an approximate expression for the magnitude difference Δm between these objects. Your expression should have Δm proportional to Δf. Homework Equations Δm = m2 - m1 = 2.5 * log(f1/f2)...
  34. P

    Relation between Critical Realism, Ontology and Epistemology

    Hello, I have to present Critical Realsim theory to class. I have been coming across words like Ontology and Epistemology. I made effort to see what those terms are and their relation to critical realism but I couldn't understand it. It talks philosophy. Can some help me to understand in simple...
  35. S

    Cauchy-Riemann: Is the Relation ∂x/∂y = -∂y/∂x True in General?

    Considering f(z) = z where z is analytic. z = x + iy. f(z) = u + iv = x + iy. Hence u=x and v=y. Using Cauchy Reimann eqns. ∂u/∂x = ∂v/∂y =1 and ∂u/∂y = -∂v/∂x where u=x and v=y hence ∂x/∂y = -∂y/∂x is this relation true in general?
  36. F

    Equivalence relation and equivalence class

    i have two relations given to me which are both defined on the integers Z by relation 1: x~y if 3x^2 -y^2 is divisibale by 2 and relation 2: x~y if 3x^2 -y^2 ≥0 I have used three properties to figure out that relation 1 is eqivalence relation as it stands for all three properties i.e...
  37. J

    Finding general difference polynomials' recurrance relation

    Hi! I have a sequence of difference polynomials (which I obtained by the method of finite differences) and I would like to find out if there is a recurrence relation between them. The generating function of general difference polynomials is given by: How would one write the...
  38. A

    Mathematical Logic, Interpretation, Satisfiable, Consequence relation

    Theorem : let A be a set of formulas, a be a formula For all A and all a, Every interpretation which is a model of A is also a model of a iff not (Sat A) U {~a} Proof Every interpretation which is a model of A is also a model of a iff(1) there is no interpretation which is a model of A but...
  39. S

    Relation between commutator, unitary matrix, and hermitian exponential operator

    Homework Statement Show that one can write U=exp(iC), where U is a unitary matrix, and C is a hermitian operator. If U=A+iB, show that A and B commute. Express these matrices in terms of C. Assum exp(M) = 1+M+M^2/2!...Homework Equations U=exp(iC) C=C* U*U=I U=A+iB exp(M) = sum over n...
  40. P

    Black Holes Relation to an Accelerated Expanding Universe

    Hello, Let me first start off by saying that I have no formal Education or background in Physics or Astronomy save for one course during college. This is simply posing an idea I had while reading an article on the acceleration of the expanding universe and how it could have a correlation with...
  41. U

    Relation between Time-Dilation and Radioactivity

    Is it true that all the Experiments which are intend to prove Time-Dilation of SR 'directly', are based on radioactive half-lives extension ? For example, cesium atomic clocks in GPS satellites, Muon decay etc. Moreover, if it is true, ... and correlations between nuclear decay rates...
  42. C

    Need help in solving a recurrence relation

    Hey! I was trying to find the expected time an algorithm takes to solve a certain problem, and I ended up in a very nasty recurrence relation of this form: a_{k,k} =...
  43. D

    Frequency and Voltage relation

    Hi, I'm confused about the meaning of the term frequency used in electronics. I'm not sure if I understand what it means. For example: There a number of frequencies travel through a single cable television, at the end point does the de-multiplexer recognizes each signal by its voltages...
  44. J

    Hi all,Let λ>0 and define an equivalence relation on

    Hi all, Let λ>0 and define an equivalence relation on ℝn-{0} by (x~y) \Leftrightarrow (there is an s\inZ such that λsx=y) I would like to know what the quotient space ℝn-{0}/~ looks like. I know that it is a set of equivalence classes. To understand it better I wanted to see how it...
  45. X

    Quantum Mechanics: Uncertainty and Commutation relation

    I am stuck on one part of my Quantum Mechanics HW. Above the question it says "Try and answer the following question." So I can only assume that he isn't looking for something incredibly detailed. (Ill explain why after the question is given.) Homework Statement What is the meaning of the...
  46. S

    Equivalence Relation on ℝ: xRy if x≥y | Symmetry and Transitivity Explained

    Homework Statement Determine whether the given relation is an equivalence relation on the set. Describe the partition arising from each equivalence relation: xRy in ℝ if x≥y Homework Equations Reflexive: for all x in X, x~x Symmetric: for all x,y in X, if x~y, then y~x Transitive...
  47. C

    Relation between binding free energy and solubility

    Suppose we have a ligand binding to a receptor in solvent medium. I am interested to know whether there is any relation between "Binding free energy" and "Solubility". Extemely sorry if I posted my question in the wrong section. I'd be glad if anyone could help me out with this. Regards...
  48. C

    Static Friction: Max Force Magnitude Applied?

    Homework Statement Which of the following statements are true about Fs, max in the equation mu=Fs, max/Fnormal? I. Fs, max is exerted perpendicular to the surfaces in contact. II. Fs, max represents the maximum value of the force of static friction. III. On a level surface, the magnitude of...
  49. Y

    Calculating 2D Dispersion Relation with Different Atom Types

    I have derived 2D dispersion relation which has the same atoms. But I also need to calculate this 2D dispersion relation with two different atoms. One atom is located at the center and the other type of atoms surrounds this atom. But I am not sure how ı should calculate it because only...
  50. A

    Phonon and dispersion relation

    hello I am new in this forum.. and i would like to ask first this is statement that i confused about 'At low values of k (i.e. long wavelengths), the dispersion relation is almost linear, and the speed of sound is approximately ω a, independent of the phonon frequency. As a result, packets of...
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