Concept Definition and 1000 Threads

  1. M

    Most effective method to self-learn a new mathematical topic and or concept?

    I am quite sure at least some members here have their own particular way to go about learning a new topic or concept. But, does anyone have any advice for self learning something that is completely new or different without the help from classmates or a teacher about? I am self learning math...
  2. G

    I How Does Helmholtz Free Energy Change During Constant Temperature and Volume?

    This is really basic,and I’m not seeing something obvious,but I’d appreciate help with this concept. In differential form dA= -tds-pdv. However s and v are the natural variables for this free energy and are held constant . As I understand it the Helmholtz free energy is the energy available to...
  3. E

    Simple Concept Question Regarding Impulse and Momentum

    It's simple to everyone but me haha 1. Homework Statement We toss an egg onto the floor, and it breaks. We toss an egg onto a pillow on the floor, and it does not break. The egg that does not break experiences a smaller: A. Impulse B. Change in momentum C. Maximum ForceHomework Equations...
  4. D

    I Physics -- Need help understanding the concept of resonance please

    I need help about the concept of resonance. I will be thanksful if someone help me. Please consider a system has two natural frequencies, and resonance will occur at two these natural frequencies. Now my question is what is different between these two renosances that has occured? And Which...
  5. O

    I Concept underlying recent Serra-Lutz cold-to-hot experiment

    Hi, I'm trying to understand in a simple, non-mathematical way the basic concept underlying why a particular, very recent experiment turned out the way it did. The experiment, by Serra and Lutz entitled 'Reversing the thermodynamic arrow of time using quantum correlations', demonstrated an...
  6. P

    Help me find the modern terminology for an old philosophical concept

    There used to be a term called 'logical space' where objects have their properties (or facts) defined by their relation to other objects in said 'logical space' along with their potential modalities included in this sort of 'space'. Here is the definition provided here: I've heard the modern...
  7. N

    Did I Make Mistakes in Calculating the Potential of a Charged Sphere?

    Homework Statement A sphere of radius R has a volume charge density proportional to distance from center. Total charge contained in the sphere is Q. If electric potential at infinity is taken to be zero , potential at it's center is Homework Equations Here given are ρ= βr where β is a constant...
  8. S

    Springs and Splitting Mass Concept Confusion

    Am I thinking about this problem correctly? "A block is attached to a horizontal spring and oscillates back and forth on a frictionless horizontal surface at a frequency of 3 Hz. The amplitude of the motion is 5.08 x 10-2 m. At the point where the block has its maximum speed, it suddenly splits...
  9. PainterGuy

    Understanding gradient concept

    <Moderator's note: Moved from a technical forum and thus no template.> Hi I was trying to understand the concept of gradient. I'm using Thomas's Calculus 12th Ed. Please have a look here. Using the Definition 1, the answer came to be 3.54. Then, I tried to attempt the same problem using...
  10. G

    B Concept of the stability of the speed of light

    Help with the question of the concept of the stability of the speed of light. I gather that current atomic clocks are based upon the speed of the electron around their nucleus, which is a function of the speed of light. Measurements of the speed of light that depend upon atomic clocks therefore...
  11. R

    Follow-up Question to: The Concept of Pressure in Bernoulli’

    I have been looking all over the net for answers for the unintuitive relationship between pressure and velocity in Bernoulli's equation and this thread (https://www.physicsforums.com/threads/the-concept-of-pressure-in-bernoullis-principle.585231/) answered most of my questions. I have one last...
  12. Gary Smith

    Exploring Consciousness: A Non-Scientist's Perspective

    Hi, I am Gary. I like to stretch the limits of my conceptualizing, and catch up to it with experiential awareness. This characteristic leads me to write a blog of experiments, realizations and experiences, such as having a conversation with a stone about 'cooperative networks of conscious...
  13. Pushoam

    B Event in SR: Explained w/ Example for Better Understanding

    Event is anything which can be located by (x,y,z,t). We don't need this concept in Galilean transformation. I was first introduced to the concept in the beginning of Special relativity. I haven't understood the significance of this concept till now. Can anyone please illustrate me using an...
  14. donaldparida

    Fundamental problem regarding mole concept

    Background: Amount of substance is a fundamental physical quantity which has mole (mol) as it's SI unit. Therefore all expressions for amount of substance should have the unit mole on simplification. Therefore, if A = Amount of substance (normally in moles), m = Mass of the substance in a...
  15. Waggles

    Renewable Energy Concept - Stirling Engine Composting

    So I've got this crazy idea. To put it simply, to use the heat from anaerobic composting to power hot-air engine, specifically a Stirling Engine. Based solely on my own reading, the center of a closed composting heap can reach anywhere from 120-160 degrees without killing the microorganisms...
  16. FallenApple

    A Interpreting the Association Between y and x while Holding the Group Constant

    Say we have a phenomenon where we want to see if x is related to y where x is continuous. Further, there is an opposite effect of x on group 1 compared to group2. Say for group 1, increasing x is associated with increasing y, for group 2, increasing x is associated with decreasing. (this is not...
  17. BillTre

    New Concept for Zero Emission Natural Gas Power Generation

    Science mag news article on a new electrical power plant being set-up by a start-up. It burns natural gas with pure oxygen and runs turbines with CO2. It makes water rather than using it and is in theory close to competitive economically. . Sounds good to me, but I'm no engineer.
  18. Adam Rabe

    Tone hearing frequency concept question

    Homework Statement Homework Equations Dont know any sorry The Attempt at a Solution I tried imagining the ear as some sort of harmonic pipe with the sound coming inside as a sine wave. The question says the sine wave is not fully sinosoidal and is flattened at the top and bottom. I don't...
  19. A

    Help to understand the concept of Power

    Power is described as the Velocity at which Force is applied to an object (P=F*d/t) However, how are the Force and Velocity independent? Doesn't the Force applied affect the Velocity of the object? For example, let's say you want to lift a 19.62N (2kg*9.81m/s^2) object upwards 1 meter in 1...
  20. D

    Offset Torque: Solving the 1000N Problem

    Hello guys, I am doing some basic design work and can't remember how offset torques work. I am doing the sum of the torques should be equal to 0 in order to find the tipping point around either of the wheels. My problem is with the 1000N applied at to top taking the pivot point around the...
  21. Greg Bernhardt

    Most misunderstood physics concept

    What do you think is the most misunderstood concept in physics and why? I'm guessing it's something in QM or relativity, but maybe somewhere else?
  22. srinaath

    Electrical DIY wireless power transfer device concept

    i am planning to do a small diy wireless power transfer device. The circuit of the transmitter is receiver has just the coil and load arrangement. my query is, (please correct me if am wrong) -->to induce a voltage in the secondary coil, there must be a varying magnetic field right? -->but...
  23. binbagsss

    I Solve Null Geodesic: Affine Parameter & Coordinate Time - Q1,Q2,Q3

    I am asked a question about how far a light ray travels, the question is to be solved by solving for the null goedesic. I am given the initial data: the light ray is fired in the ##x## direction at ##t=0##. The relvant coordinates in the question are ##t,x,y,z##, let ##s## be the affine...
  24. soumobrata

    B Microcanonical vs. Canonical Partition Functions: What's the Difference?

    What is the difference between micro canonical Partition function and canonical Partition function? Is the mathematical expression of the above two Partition function are same? If it is then why?? [emoji29]
  25. A

    I Growing food in space - a 3rd concept

    To grow food in space, I have read about two designs of greenhouse. One is a pressurised greenhouse with wide expanses of thickened glass. The other is indoor stacks of shelves with LEDs driven from solar PVs outside. But would this third design work? Have a rotating mirror to focus light into...
  26. M

    -- E/M conceptual question regarding electric potential

    So in a graph where V is a function of x, when the slope is negative what does that mean about the direction of the field along the x axis? What about when the slope is positive?
  27. Pyrus

    I What is the basic concept of the spin of a particle

    What is the basic concept which decides the spin of a particle. Like, electron has a spin of +- 1/2... What do this 1/2 signifies. Other spins are also there like 1 and 2. What do they signify? Is there any possibility of any particle with spin other than 1/2, 1 or 2?
  28. binbagsss

    I Congruence Subgroups and Modular Forms Concept Questions

    1) Defintion : A congruence subgroup of level ##N## is one that contains the principal subgroup at level ##N## which is defined as ## (a b c d) \in SL_2(Z) : a,d\equiv 1 (mod N), b,c \equiv 0 (mod N) ## (apologies ## ( a b c d)## is a 2x2 matrix.) The Hecke group is one such example given by...
  29. FallenApple

    I Why was time dilation under GR a new concept?

    Edit: I mean a new concept as in new with regards to the century before. I'm aware that lorentz and maybe others had some idea even before GR So time slows down for the individual under a stronger gravitational field than for an individual under a weaker gravitational field. But why does this...
  30. R

    Constructive interferance homework (concept) help

    Problem: Consider a 360-nm thick oil film floating on the surface of the water. The indices of refraction of the oil and water are 1.5 and 1.33. The surface of the oil is illuminated from above at normal incidence with white light. (A) Find the shortest wavelength of light in the 400nm to 800 nm...
  31. Clara Chung

    Question about x-ray, concept confusion

    1. Must the electron brought to rest(in one step or many steps) in Bremsstrahlung effect? 2. Besides from a coming electron knocking off an electron on the shell then another electron fills the void, can the coming electron just excite an electron on the shell to a higher state and release a...
  32. Clara Chung

    B Matrices concept confusion....

    In the photo that is a matrix B. B^3 + B = 2B^2 +2I from calculations. But why not B must be equal to 2I, the reason is as follow, B(B^2 + I ) = 2(B^2 +I) B(B^2 + I)(B^2 + I)^(-1) = 2I (B^2 + I)(B^2 + I)^(-1) so B = 2I why is my concept wrong? please explain to me.
  33. H

    Need help understanding this concept regarding melting ice

    Homework Statement In an insulated vessel, 265 g of ice at 0°C is added to 630 g of water at 17.0°C. (Assume the latent heat of fusion of the water is 3.33 105 J/kg and the specific heat is 4 186 J/kg · °C.) a) What is the final temperature of the system? b) is already solved Homework...
  34. Austin Chang

    I'm confused by this concept 2-d motion dumb question

    Homework Statement A cart that is rolling at constant velocity on a level table fires a ball straight up. When the ball comes back down, will it land in front of the launching tube, behind the launching tube, or directly in the tube? Explain. Homework EquationsThe Attempt at a Solution Why...
  35. Deebu R

    I Need help with concept based questions

    Let f(x) and g(x) be twice differentiable functions on [0,2] satisfying f"(x)=g"(x), f'(1)=4, g'(1)=6,f(2)=3 and g(2)=9.Then what is f(x)-g(x) at x=4 equal to? I honestly have no idea how to do it.Please help.
  36. R

    B What is the concept of Physics of Cymatics (of a liquid)

    Hi, Could someone please help me about what is the physics concept behind Cymatics. Is there a formula which establishes the patterns form on a liquid when the frequency or amplitude are changed? Thanks.
  37. Jonny Cruz

    B Are there any researchers on the concept of time?

    I am 16 and I'm doing a research project titled "Is our perception of time an illusion?" I've got many articles and other sources that have helped me develop an essay, but I am also expected to get an interview with someone which is extremely hard as it is such a specific topic and doesn't seem...
  38. Jehannum

    I The concept of 'unknowns' in equations

    You can solve an equation with one unknown. You need two different equations for two unknowns, and so on. This implies a binary distinction between 'known' and 'unknown'. But are there grades or shades of unknown? For instance, if you know that a variable is negative but not its magnitude, can...
  39. F

    Space vector analysis of 3 phase -- stuck on a concept

    I am trying to understand space vectors in 3 phase machines. If you have a balanced 3 phase system, the 3 phasors of voltage, current or whatever... should sum to 0. i<0 + i<-120 + i<-240 = 0. But in this image of a rotating space vector ...
  40. artriant

    Artificial gravity concept -- Rotating structure in space

    Hello everyone, i m working on a full circle space centrifuge concept. I try to support it with some maths but i don't want to dive into crazy details. I used alrdy lot of countermeasures to dangerous effects.I have problems similar to bridge mechanics. The design is not solid so i need to be...
  41. donaldparida

    B What is the need for introducing the concept of G.P.E?

    What is the need of introducing the concept of gravitational potential energy in physics? Can't we simply say that when an object is lifted up it falls down because of the force of gravity acting on it instead of saying that it has G.P.E and so it is falls down?
  42. SadPanda6022

    Why Do We Not Calculate Angle Change in Plastic Container?

    Homework Statement In this lab we used a half-circle container filled with water. Multiple angles are given to measure through the liquid in the container, calculating using snell's equation. However I don't understand why we do not have to calculate for the change in the angle from the plastic...
  43. Valour549

    I Inconsistencies in the concept of limits

    I understand that 0.9999... = 1 is true because in limit theory "getting arbitrarily close" means that they actually are equal. I'm also aware of the epsilon-delta definition of limits. But I feel like there are some inconsistencies in this concept; I'll explain using two scenarios. Case 1...
  44. Clara Chung

    Rotation dynamics pulley concept confusion

    Homework Statement A light string is passed over a pulley and two masses m1 and m2 are suspended from the two free ends. The pulley is a uniform circular disc of mass M. Find the linear acceleration of the two masses. Friction may be neglected. Homework Equations I through center of the disc =...
  45. Karan Punjabi

    Understanding the Concept of Capacitor: Q&A

    Guys, I am learning about the concept of capacitor,but I am confused in some things that if i kept the amount of charge constant between two plates of a capacitor and then increase the potential diff. this means that i decreased its capacitance right? If I am wrong then please explain the given...
  46. S

    A Concept of duality for projective spaces and manifolds

    I firstly learned about duality in context of differentiable manifolds. Here, we have tangent vectors populating the tangent space and differential forms in its co-tangent counterpart. Acting upon each other a vector and a form produce a scalar (contraction operation). Later, I run into the...
  47. T

    Help w/ understanding concept of distributing a neg. sign

    Homework Statement Basically, I have to distribute this negative sign in this math expression: - (-x^2 + 12x +24) Homework Equations none The Attempt at a Solution I know from the rules that we get: (x^2 - 12x - 24) My question is why do we distribute the negative sign to begin with? I...
  48. Masontc

    I Does this concept have a name? (looping/overlapping time)

    I'm a student working on a short experimental animation. I've always had a fascination with the number 24 because it's divisible by 6 four times and divisible by 8 three times... you can add different numbers at a different rate and end up at the exact same number after a specific amount of...
  49. JohnGaltis

    Double Slit Question with Thin Lens concept

    Homework Statement Consider a double slit experiment with a light source of 540nm. Slit separation is 4mm. A thin glass plate is placed in front of one of the slit,, resulting in each bright fringe moving to the location of the adjacent bright fringe. Find the minimum thickness of the glass...
  50. egio

    I Difference between integral and antiderivative?

    Hello, I still don't really understand what an antiderivative is, besides its ability to "undo" derivatives, its relation to integrals, and what the difference between the two even is. It would also be great to know how to visualize an antiderivative. I've tried looking further into the...
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