Negative Definition and 1000 Threads

In mathematics, a negative number represents an opposite. In the real number system, a negative number is a number that is less than zero. Negative numbers are often used to represent the magnitude of a loss or deficiency. A debt that is owed may be thought of as a negative asset, a decrease in some quantity may be thought of as a negative increase. If a quantity, such as the charge on an electron, may have either of two opposite senses, then one may choose to distinguish between those senses—perhaps arbitrarily—as positive and negative. Negative numbers are used to describe values on a scale that goes below zero, such as the Celsius and Fahrenheit scales for temperature. The laws of arithmetic for negative numbers ensure that the common-sense idea of an opposite is reflected in arithmetic. For example, −(−3) = 3 because the opposite of an opposite is the original value.
Negative numbers are usually written with a minus sign in front. For example, −3 represents a negative quantity with a magnitude of three, and is pronounced "minus three" or "negative three". To help tell the difference between a subtraction operation and a negative number, occasionally the negative sign is placed slightly higher than the minus sign (as a superscript). Conversely, a number that is greater than zero is called positive; zero is usually (but not always) thought of as neither positive nor negative. The positivity of a number may be emphasized by placing a plus sign before it, e.g. +3. In general, the negativity or positivity of a number is referred to as its sign.
Every real number other than zero is either positive or negative. The non-negative whole numbers are referred to as natural numbers (i.e., 0, 1, 2, 3...), while the positive and negative whole numbers (together with zero) are referred to as integers. (Some definitions of the natural numbers exclude zero.)
In bookkeeping, amounts owed are often represented by red numbers, or a number in parentheses, as an alternative notation to represent negative numbers.
Negative numbers appeared for the first time in history in the Nine Chapters on the Mathematical Art, which in its present form dates from the period of the Chinese Han Dynasty (202 BC – AD 220), but may well contain much older material. Liu Hui (c. 3rd century) established rules for adding and subtracting negative numbers. By the 7th century, Indian mathematicians such as Brahmagupta were describing the use of negative numbers. Islamic mathematicians further developed the rules of subtracting and multiplying negative numbers and solved problems with negative coefficients. Prior to the concept of negative numbers, mathematicians such as Diophantus considered negative solutions to problems "false" and equations requiring negative solutions were described as absurd. Western mathematicians like Leibniz (1646–1716) held that negative numbers were invalid, but still used them in calculations.

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  1. K

    What does a negative potential energy mean?

    A consequence of Coulomb's law is that oppositely charged particles have a negative potential energy. I'm having trouble undsrstanding how anything can have a negative potential energy and what consequences that has. Does it just mean the change in potential energy is negative or is it a matter...
  2. Gene Naden

    Positive and negative plane wave solutions of Dirac equation

    I continue to be occupied with the first chapter of Lessons on Particle Physics by Luis Anchordoqui and Francis Halzen. The link is https://arxiv.org/PS_cache/arxiv/pdf/0906/0906.1271v2.pdf. I am on page 24, where they derive equations 1.5.67, which are: ##(\gamma^\mu p_\mu-m)u(p)=0## and...
  3. bbbl67

    I Is Negative Mass Possible? Exploring the Latest Research and Controversy

    Was reading this article: https://phys.org/news/2018-01-device-negative-massand-lasers.html#jCp The article claims that these guys have created negative mass? If that's true, isn't that ground breaking? It's one of those extraordinary claims that needs extraordinary proof, doesn't it? Or is...
  4. F

    I Negative Mass and Hawking Radiation

    Matter with negative mass, herein called “negative matter”, is different from antimatter. P.A.M. Dirac, on theoretical grounds, proposed the existence of antimatter, and its existence was later confirmed by experiment. Antimatter is the opposite of ordinary matter in some ways, but just as...
  5. Jamesgortrig

    Is the work caused by the force of friction negative?

    Homework Statement A student pushes a 0.65kg box Ali g a desk. When he stops pushing the book, it moves 85cm before stoping (slowing down in this period). Coefficient of friction between book and Table is 0.27.Calculate the work done on the book by the friction. Should it be positive or...
  6. S

    Potential difference in between positive and negative charge

    Homework Statement Two point charges Q1= +5.00 nC and Q2 = -3.00 nC are separated by 35.0cm. What is the electric potential at a point midway between the charges? Homework Equations V = Ke(q/r), PE = Vq[/B] The Attempt at a Solution This question is from Serway textbook. The answer is...
  7. C

    German energy prices go negative

    Well for awhile at least. I'm a bit surprised they couldn't export the excess. The Independent: Germany energy consumers paid to use power over Christmas as supply outstrips demand. http://google.com/newsstand/s/CBIwn6XOoTc
  8. M

    Work done by the system, positive or negative?

    My chemistry course says that work done by the system is negative, but physics course says that work done by the system is positive, I'm sure I'm missing something and I really need to understand it. Thanks.
  9. bananabandana

    I Negative and Positive energy modes of KG equation

    If we have the normal KG scalar field expansion: $$ \hat{\phi}(x^{\mu}) = \int \frac{d^{3}p}{(2\pi)^{3}\omega(\mathbf{p})} \big( \hat{a}(p)e^{-ip_{\mu}x^{\mu}}+\hat{a}^{\dagger}(p)e^{ip_{\mu}x^{\mu}} \big) $$ With ## \omega(\mathbf{p}) = \sqrt{|\mathbf{p}^{2}|+m^{2}}## Then why do we associate...
  10. J

    Microbiological Fuel Cell: Negative Voltage

    Hello! I've been working on a few soil based MFCs and I have been monitoring my voltage and energy output for a week now. I've made the electrodes by covering stainless steel metal meshes with activated carbon using epoxy. I've gotten some funky results as attached. As you can see... the...
  11. axer

    Work Done by Gravity - Positive or Negative

    Homework Statement Homework EquationsThe Attempt at a Solution I first said it's B, since force throws up = positive. gravity down= also positive, please help asap thanks
  12. C

    I Negative Kelvin? How Is It Possible?

    Negative Kelvin http://science.sciencemag.org/content/339/6115/52. How is this possible? If anyone could help me understand this I'd appreciate it.
  13. I

    Why is there a negative charge on the oxygen atom with the single bond?

    My question is that why is the negative charge on the oxygen atom with the single bond, why not on the oxygen atom with the double bond? I am confused. Source: https://chem-net.blogspot.in/2012/01/simple-procedure-for-writing-lewis.html
  14. A

    Negative work and electric potential energy

    I am confused how a charge could have negative work done. To clarify, I was doing a problem earlier in which a positive charge and negative charge are moving towards each other. I used the equation work = Δv * q And when I was doing this, the change in electric potential, Δv, was negative, and...
  15. A

    Finding the final speed of a Positive and Negative Charge

    Homework Statement This is an example problem I found on khan academy and it didn't have an official problem statement... So I am going to have to make up my own problem statement from what was given. I can link the video if any of you want to see it. A positive charge 4uC and a negative...
  16. G

    Getting negative current on Zener Voltage Reg Circuit

    i've built a bridge rectifier with a Zener Voltage regulator. 12V peak secondary 3300uF Capacitor 1k ohm load 1k ohm series resistor for the zener and a 1n4728A Zener diode. i'm getting a 2.8V steady voltage, but when i measured the current going through the load with my DMM it's measuring...
  17. D

    Differential Amplifier with negative feedback

    Homework Statement [/B] Homework Equations Adiff(single-ended)= 1/2gm*ro||Rd β=R2/(R1+R2) The Attempt at a Solution I am really confused as to how to find A. I know the feedback of the circuits around the R2 and R1, but I don't understand how the open loop gain can be found. Can someone...
  18. Allen_Wolf

    B Exploring the Possibility of Negative Mass: Implications and Limitations

    If we imagine two particles A and B. A has positive mass and B has negative mass and initial velocity 0. This happens in a non interfering environment . If both theses has opposite and equal value of mass, shouldn't they be repelling each other? F=G. (M.-m)/r^2. Value of F should be negative.
  19. V

    B Can Fermions Exhibit Negative Chemical Potential Like Bosons?

    Is possible and what does it mean if a chemical potential is negative? I mean that for boson it means that in environment is "needed" boson (photon) and is possible to create him. Is it true? And what about for fermions? Could it mean that it is pleasent for environment to creat some fermion? Or...
  20. G

    A Can Weyl Tensor Look Like Negative Mass?

    The smoothed Weyl tensor can look like space that contains a non-zero Einstein tensor. To verify this, consider that gravitational waves carry mass away from (say) a rotating binary, so the apparent mass at infinity of a large sphere containing a radiating binary will be greater than the mass...
  21. Greg Bernhardt

    Negative pressure in house after winterizing

    I sealed my attic door and a set of 3 old windows downstairs with plastic. When everything else is closed up the two sets of plastic become extremely tight and you can see/feel the pressure pushing the plastic into the house. Almost to the point of ripping the tape off holding the plastic. Today...
  22. Adgorn

    B Square root of a negative number in a complex field

    Mod note: Fixed all of the radicals. The expressions inside the radical need to be surrounded with braces -- { } (This question is probably asked a lot but I could not find it so I'll just ask it myself.) Does the square root of negative numbers exist in the complex field? In other words is...
  23. F

    Can a set include negative infinity and be bounded below

    Homework Statement Prove that {##x \epsilon \mathbb{R} : x^2 \ge 1##} is "not" bounded below. EDIT: I Looked closely and realized there is a "not" that we all had to write in...sorry if you lost some time.. Homework Equations Defintion: We say a nonempty subset ##A## of ##\mathbb{R}## is...
  24. C

    I Exploring Negative Kelvin: Is It Possible?

    I recently saw an article that talked about negative Kelvin. How's this possible?
  25. A

    Negative Sensible Heat Flux at Earth's Surface

    I'm a bit confused as to how to imagine a negative sensible heat flux near the Earth's surface. Negative means that sensible heat is moving towards the surface. My book states that that would mainly occur at nighttime. During day there is a positive sensible heat flux and sensible heat moves...
  26. S

    Chemistry Determining the positive and negative poles of a molecule

    Homework Statement For the molecule CHCl3, a) Draw the electron dot diagram and structural formula b) predict the shape c) predict whether it is polar or non-polar, and justify your prediction. Indicate the positive and negative poles. Homework Equations none The Attempt at a Solution [/B]...
  27. T

    What is the relationship between critical angle and negative refractive index?

    Homework Statement [/B] Homework Equations Snell's Law: n1sin(i)=n2sin(r) Critical angle=sininverse(n1/n2) [**only works when n2>n1] If a light beam is incident at an interface of 2 mediums(with r.i n1 and n2) at an angle greater than the critical angle,the interface acts as a...
  28. A

    I Negative values for Gaussian Distribution

    So in my Physics lab, we divided into groups and our task was to throw darts on a target containing 13 bins. The bins look something like the image below. At the end, our class combined our average, standard deviation, and standard error. I made a Gaussian Distribution and I noticed that the...
  29. caters

    I Could Gravity Ever Be Negative?

    Now, I know that it is theoretically possible for negative mass to exist and for negative energy to exist. But any gravity would act on all objects and all energy, no matter if that mass and energy is positive or negative. So negative gravity would for example, pull a person upwards. Now yes, I...
  30. A

    Positive or negative final velocity? Constant acceleration

    Homework Statement A car is moving with a constant velocity of 18 m/s for 5 seconds, if in the next 5 seconds it travels a distance of 40 m, what is its final velocity? Homework Equations Δx= vit+ 1/2 at^2 vf= vi+at vf^2 = vi^2 + 2a (Δx) The Attempt at a Solution So I tried doing it different...
  31. R

    What does negative potential energy mean?

    In the case of lifting a box, I know potential energy is negative because negative work is done by gravity. What does the negative part of -PE denote? Does it denote the direction of the energy or does it mean that energy is being lost? But how is energy being lost if the box gains more...
  32. T

    A Is Negative Mass Related to Antimatter in Physics?

    In physics we cannot easily imagine “negative” energy for a particle (not a field) in order to have “negative” mass, although the first concept of Dirac for antiparticles was that they were “holes” that were opposite to particle existence and there was a minus in front of mc2.Regardless of...
  33. M

    MHB Negative minimum of the average variable cost function

    Hey! :o Can the minimum of the average variable cost function be negative? (Wondering) Suppose we have the cost function $K(x)=x^3-9x^2+11x+100$. The variable cost function is then $K_v(x)=x^3-9x^2+11x$. The average variable cost is $k_v(x)=\frac{K_v(x)}{x}=\frac{x^3-9x^2+11x}{x}=x^2-9x+11$...
  34. M

    Negative vs Positive work on an escalator

    Homework Statement You are in a large store that has escalators connecting its floors. The stairs of each escalator move smoothly and steady either uphill or downhill as they carry passengers between floors. You get off the "up" escalator on the second floor and board the "down" escalator. This...
  35. L

    B Representation of complex of square root of negative i with unitary power.

    Can ##sqrt(-i)## be expressed as a complex number z = x + iy with unitary power?
  36. D

    B Understanding Negative Exponents and Bases in Algebraic Expressions

    Going through a problem and and I keep getting it wrong and I'm not sure why. In a part of the problem, the expression ##\left(-3\right)\left(-r^4\right)\left(-s^5\right)## comes up and the solution that it's giving me is ##-3r^4s^5## Wouldn't the last factor be ##-s^5## since the power of a...
  37. K

    Negative derivative instead of positive

    Homework Statement Homework Equations Differential of a product: $$d(uv)=u\cdot dv+v\cdot du$$ The Attempt at a Solution $$dV=\pi \left[ -\frac{1}{x}x^2+2x\left(-\frac{x}{3} \right) \right]dx=-\pi x^2dx$$ If dx>0 dV<0, it's wrong, the volume increases
  38. E

    Attraction of a positive and negative charge

    No one could ever explain to me the mechanism how attraction of positive and negative charge works. Can you? (Exchange of (virtual) photons only explains repulsion.) An electrical field is playing hide and seek.
  39. X

    When is acceleration positive or negative?

    Homework Statement In this problem, the solution says that aB= -(aA/6). But from what I know, acceleration is positive whenever an object is speeding up in the positive direction or when an object is slowing down in the negative direction. According to the problem, car B is slowing down and...
  40. T

    MHB Negative numbers with fraction problem: simplify 3/4 [ 5/6 ( -18/25 ) + 1/2 ]

    Hey guys, I am seriously confused by this problem. 3/4 [ 5/6 ( -18/25 ) + 1/2 ] I would appreciate it if someone shows me the step by step process. Thanks in advance :)
  41. C

    B Why Negative Hydrogen/Deuterium Ion Generators?

    Auto-Search gives me some hints. I did a Google for "Hydrogen Ion Generator" and got a load of hits about "Negative Hydrogen Ion Generators". They almost seem to be 'fusion specific'. Are they used because the required end result is a neutral beam of Hydrogen/Deuterium for injection into the...
  42. RyderP

    Warping an Average Guy Across Town: Exploring Negative Mass

    How much negative mass would it take to warp, say, an average guy across town?
  43. S

    Is it possible that an electron can have a negative mass?

    I have this brain worm and it's been bugging me for ages. I don't know enough about anything to be able to answer this but when I heard a theory that an electron can be in 2 places at once but then appears to be in a specific location when observed I started wondering how this could be possible...
  44. C

    Can Negative Mass at near Speed of Light go Back in Time?

    Sorry if the title was a little vague, character limits. The question at hand is this; If you were to accelerate an object to near speed of light, time around it would speed up, thus forward time travel. We all know this and I am no expert in this area but am incredibly curious. (Assuming we can...
  45. M

    I Twin paradox in GR - negative time?

    I was reading the wikipedia page on the twin paradox (https://en.m.wikipedia.org/wiki/Twin_paradox). It says: The mechanism for the advancing of the stay-at-home twin's clock is gravitational time dilation. When an observer finds that inertially moving objects are being accelerated with...
  46. T

    Newton's Laws - Positive & negative direction

    Hi, While solving homework problems, I start by defining a positive-y direction and a positive-x direction. Let's say up and to the right. Until now, I've applied this same rule to all objects in each problem, no matter the direction the object moves. But it seems I have not understood this...
  47. martin25p2

    I Relationship between negative mass, energy and antimatter

    What is the relationship between negative energy, negative mass and antiparticles? I have read some articles but I am still confused. Does negative mass exist? Does negative energy exist with the exception of the Kasimir effect which I understand. Are antiparticles really only the negatice...
  48. V

    B Negative potential energy and negative mass

    My question is: If gravitational potential energy is normally negative, and E=m•c^2, doesen't that means that negative mass could exist? (I don't know much about general relativity so please explain as simple as posible)
  49. H

    B Definite integrals with +ve and -ve values

    I understand that if you have a function in which you want to determine the full (i.e. account for positive and negative values) integral you need to break down your limits into separate intervals accordingly. Is there any way in which you can avoid this or is it mathematically impossible? If...
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