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. S

    Momentum Conservation: How to Reconcile a Negative Value?

    Maybe a silly question but on the above question using the conservation of momentum: momentum before firing (0) = momentum after firing (55*35)+(M*2.5) If I re-range the above it's M = -(55*35)/2.5 = -770kg. I can I reconcile that minus sign (basically get rid of it)? Thanks
  2. H

    B Apparent missing negative phase oscillation energy - where is it?

    When an oscillator produces waves - let's say they are highly focused - that are damped by a second negative phase oscillator, where is the wave energy? The energy in each set of waves must still exist. Has it become hidden?
  3. Johnstonator

    Engineering Determining if voltage or current is positive or negative with sources

    So I'm confused on a few things about this circuit. I know my math is right (since I got the absolute values correct), but the signs are off since I can't tell when the voltage, current or if the general power equation is positive or negative. A) So my first question is, where is the current...
  4. T

    Negative Concave Lens - Creating a Beam Expander

    I am trying to create a beam expander. I purchased 3 double convex and 3 double concave lens (200mm, 300mm and 500mm). But for the diverging concave lens I need a negative -500mm lens. What exactly is a negative concave lens? I am unable to find anything on amazon or any other site that has a...
  5. J

    Understanding Loop Currents: Why is I3 Negative?

    Hello, In the following problem, when finding the equation for I2 I don’t understand why I3 is negative. Although I2 and I3 are going in different directions (clockwise and counterclockwise), at that ohm they are both going from left to right. When finding the equation of I1, I1 goes from left...
  6. M

    Physics C: Mechanics - Negative Energy and Potential Energy Curves

    I'm currently taking a course where we are working to teach older physics concepts and combine them with calculus. I was assigned to work on teaching a unit about energy; for the most part, it stays relatively consistent and can be solved algebraically. Another topic in this unit is Potential...
  7. F

    What happens to σ (conductivity) when the permitivity is negative?

    We are using the textbook by Jin, "Theory and Comutation of Electromagnetic Fields". In the section on metamaterialshe derives the dispersion relationship. He shows that when ε'= -ε & μ' = μ then the dispersion equation γ =\sqrt{jωμ( jωε +σ )} = α + jβ goes to γ = α = ω \sqrt{μ'ε'}...
  8. S

    B Commutative & Associative property of negative numbers

    Commutative property of addition. If a & b are integers then, a+b = b+a 2+3 = 3+2 5. Does not work for subtraction. 2-3 = -1 3-2= 1 Having said that, what about the special case with negative numbers (when we also move their respective signs) -5 + 7 = 2 & 7 + (-5) = 2. 15 -7 = 8 & -7 + 15...
  9. E

    B How can an atom have a negative charge?

    I have a neutral charged atom. When I bring an electron to this atom what the force will hold this electron with neutral atom?
  10. Jy158654

    How does the negative feedback amplifier below work?

    The book says that " The op-amp multiplies the potential difference between V+ and V- by the open-loop voltage gain to produce Vout." So my first question is, since we say we assume open-loop voltage gain is infinite, so does that mean the Vout produce will be infinite too? Then, the book says...
  11. Hamiltonian

    Gravitational potential energy -- Why is it always negative?

    the gravitational potential energy of a body at any point is defined to be negative of the work done by the conservative force(gravity in this case) from bringing it to that point from a given reference point. if the reference point is taken to be at infinity and the potential energy at this...
  12. Arman777

    I Exploring Negative Energy Density and its Impact on Universe Models

    There are some universe models where ##\Lambda < 0##. In this case, the energy density of the dark-energy becomes negative. At this point, does it make sense to talk about "negative dark energy density"? Or is it possible to think of this energy as curvature on space-time? Such that, ##\Lambda <...
  13. Kaushik

    What exactly is negative adsorption?

    My book states the following: When the concentration of the adsorbate is less on the surface relative to its concentration in the bulk, it is called negative adsorption. I googled it and there are barely any source that talk about negative adsorption. I saw one or two videos and I believe that...
  14. Superposed_Cat

    I Pair production via Quantum Tunneling has negative Kinetic energy?

    If we have a photon being converted to a positron-electron pair, but we lack enough energy for this to happen (hv<2Me*c^2) but the difference is smaller than the uncertainty amount, such that tunneling may be possible, would the resultant pair have net negative energy? Would tunneling even be...
  15. M

    Do plants get any negative sensations when we cut them?

    Homework Statement:: I was wondering when I break a branch of a tree, does it feel any pain or does it feel the same way I feel when I trim my nails or cut hair? Relevant Equations:: I tend to think that the latter is true as trees don't have brains or neurons. Thanks <mentor moved to...
  16. A

    Negative potential energy and capacitors

    https://www.mytutor.co.uk/answers/11559/A-Level/Physics/What-is-gravitational-potential-energy-Why-is-it-negative/ But a parallel plate capacitor is oppositely charged, so the plates attract. With the same logic don't they store negative energy and wouldn't you get the wrong answer from a...
  17. C

    I Negative Energy -- Are QI/QEI's Real?

    Hello all I wasent sure if I should post this here or in GR. I was wondering anyone could help clear something up. In my research of negative energy, the idea of QI or QEI (Quantum Energy Inequalities) has come up, limits on negative energy. I have seen many papers showing mathematical...
  18. T

    B Particle with negative mass inside a black hole horizon

    [Moderator's note: Spin off from previous thread due to topic change.] Just as an aside and not related to the OP, would a real particle with negative mass inside the event horizon follow the runaway motion? Would it be ejected?
  19. W

    Electrons @ battery negative terminal

    Does the negative terminal of a battery have a negative charge due to having a surplus of electrons? If so, then why do the surplus electrons from the negative terminal of the battery not discharge to the human body or Earth (which have a neutral charge) when touched?...thereby causing the...
  20. E

    What is the negative sign in Faraday's Law/EMF with respect to?

    A common definition seems to be that emf is an electrical action produced from a non-electrical source. So, for instance, a voltage might develop across a resistor due to a gradient of electric charge across the resistor, however this isn't an emf since the source is electrostatic in nature. As...
  21. tanaygupta2000

    Problem involving Negative Temperature

    The partition function of the given system is given by, Z = 1 + e(-ε/kT) So in the '0' energy state, number of particles, n1 = [1/(1 + e(-ε/kT))]N and in the 'ε' energy state, number of particles, n2 = [e(-ε/kT)/(1 + e(-ε/kT))]N Now according to condition of population inversion, n1 < N/2 Upon...
  22. Lren Zvsm

    What hypothetical properties would negative energy have?

    I would like to know about the hypothetical properties of hypothetical negative energy--most especially the properties that would be useful for a science fiction writer to know. If such energy existed, could it be used in a drive for space craft? An FTL drive? For a weapon? A safety...
  23. E

    B Is dx Negative in Non-Standard Analysis?

    This is more of a "housekeeping" question, though I haven't studied much in the way of infinitesimals so apologies in advance for my lack of rigour! As far as I'm aware, an infinitesimal can be thought of as a small change in some quantity. Changes can be either positive or negative, so...
  24. Kaguro

    I Understanding Op-Amp negative feedback

    In an op-amp with negative feedback, say initially the + input has some small positive value and the - input is at 0. Then the op-amp amplifies this difference, and a part of it is fed to the - terminal through resistances. This will increase - and will lessen the difference. My question is...
  25. T

    I The existence of negative gravitational plus positive inertial mass?

    The term “negative mass” gets puts forth occasionally, and it’s definitions can sometimes be unclear. the topic I’m interested in is particles which have both positive inertial mass and negative gravitational mass. So far, what theories do physicists have of speculating on the existence of...
  26. Saptarshi Sarkar

    Negative or Positive Partial Derivative

    My attempt I calculated the partial derivatives of n wrt P and T. They are given below. ##\frac {\partial n}{\partial P} = \frac{nb -1}{\left(2an-Pb-3abn^2-kT\right )}## ##\frac {\partial n}{\partial T}= \frac {nk}{\left(2an-Pb-3abn^2-kT \right ) }## I know that if the partial derivative is...
  27. B

    B What are the different ways to create negative effective mass

    Also can negative effective mass be used as a replacement in a warp drive? Also what is the most realistic warp drive theory?
  28. A

    Solving Cross Section Confusion: Adding Positive and Negative Ions

    ik that i have to add the positive and negative ions but the cross section (surface) confuses me how do i resolve this?
  29. ConradG

    Why do powerplants sell electricity for a negative price?

    Hi all, sorry in advance if this is a dumb question, I am not an electrical engineer but find the topic fascinating! My question is: Occasionally powerplants sell electricity for a negative price due to excess supply, such as in Germany...
  30. Anonymous_

    I Is There a Way to Override Reserved Symbols in Webpage Code?

    You basically just take the second derivative of the given function and multiply it by the original then multiple everything by m. I just don’t understand how the second derivative would be negative.
  31. G

    Negative carbon emissions to fight ocean acidification?

    The IPCC report strongly encouraged not only trying to get our carbon dioxide emissions down to fight climate change, but to go into negative emissions so as to draw the carbon dioxide out of the air (since it's too high as it is). Wouldn't that help to fight ocean acidification too? Because...
  32. nmsurobert

    Potential difference: positive or negative?

    I am working out an example problem from one of my textbooks and I am a bit confused on why a value is negative. The problem asks: Calculate the final speed of a free electron accelerated from rest through a potential difference of 100 V. This is a conservation of energy problem. Ultimately you...
  33. SpaceThoughts

    What Does Negative Potential Energy Indicate in Colliding Iron Balls in Space?

    Hi Everyone. I am hoping to get a little help with this: Two equal balls of iron each with a mass of 1000 kg are placed in rest in space 10 meters from each other. Because of gravity they start to accelerate towards each other, and collide in the end. I would like to know how to calculate the...
  34. Kaushik

    Negative potential energy vs Positive potential energy

    What is the physical difference between negative potential energy and positive potential energy? PS- When I was reading about surface tension I came through the following line - ' The molecules at bulk inside the fluid has lesser negative potential energy than those on the surface.' In this...
  35. AutGuy98

    MHB Proof of an Infimum Being Equal to the Negative Form of a Supremum ()

    Hey guys, I'm kind of in a rush because I'll have to go to my classes soon here at USF Tampa, but I had one last problem for Intermediate Analysis that needs assistance. Thank you in advance to anyone providing it. Question being asked: "Let $A$ be a nonempty set of real numbers which is...
  36. S

    Bernoulli equation and negative pressure

    In one pipeline with pressure P1 area A1 decrease to A2 we want to find P2 in area A2 we have bernoulli equation p1+1/2 ρv^2=p2+1/2ρv^2 with low of conservation of mass A1V1=A2V2 that we can write V2=A1/A2 V1 if we keep in bernouli equation we have P2=P1+1/2V2(1-(A1/A2)^2) my quation is...
  37. warhammer

    B Shifting of a Cosine Curve with negative phase angle values

    Continuing on from the summary, the chapter has given a graphed example. We are shown a regular cosine wave with phase angle 0 and another with phase angle (-Pi/4) in order to illustrate that the second curve is shifted rightward to the regular cosine curve because of the negative value. Now, my...
  38. N

    Negative pressure from vacuum to shunt a object upwards?

    Hi folks, I think a lot about aeronautics and physics for the purposes of helping people. I stumbled across the idea of vacuum airships as a cheap method of transporting food and water to places where it's unsafe for vehicles, or where there are no roads. We all know it's unconventional and...
  39. J

    Can energy be negative or can just a change in energy be negative?

    It sounds like the book is contradicting itself or I just don't understand something fundamental. How can energy be negative? Thank you
  40. kolleamm

    Is there any negative impact of music on the brain?

    I've been wondering this for a while. It's usually noisy in my day to day environment so I usually play music in my earphones to help me concentrate, sometimes for hours. Would there be any negative effects to this besides loss of hearing? I feel as if music may overstimulate the brain though I...
  41. Z

    Negative Charge Stability: Oxygen vs. Carbon/Nitrogen

    Why is it that it is more stable for a negative charge to be spread over 2 oxygens than one oxygen and 3 carbon atoms? Following that logic, why is it more stable to spread a negative charge over 3 oxygen atoms than over 1 oxygen atom and one nitrogen atom? Is it because the difference in...
  42. dRic2

    MATLAB Ltiview and negative step response of a linear system

    Hi, my professor gave me I code where he used to evaluate the answer of a linear system to a step increase in the input variables like this: MySystem = ss(A, B, C, D); ltiveiw('step', MySystem, 'r-', 300); My problem is that with this code I get the response only for a positive step. I'd...
  43. J

    A Negative Pressure in Solid Phase Diagram of Water

    Hi everyone! I am working with the theoretical solid phase diagram of water and I would like to know what negative pressure means. Thank you in advance!
  44. Benjamin_harsh

    Why are there no negative signs in this solution?

    ##\sum {I} = Md^{2}## ##I_{CM} = 2kg (1m)^{2} + 2kg (1m)^{2} + 2kg (1m)^{2} + 2kg (1m)^{2} = 8kgm^{2}## ##I_{P} = I_{CM} + Md^{2}## (##M## is total mass of all 4 bodies) ##I_{P} = 8 + 8(1) = 16kgm^{2}##
  45. Simpcar

    Discharge in a DC RC circuit and negative sign of current

    Hi everyone! I'm trying to understand why when writing the differential equation of a discharging RC circuit V_C-Ri(t)=0 \to q(t)/C - Ri(t)=0 we replace i(t) with -\frac{dq(t)}{dt}. I read many threads but I don't understand the physics behind this. The usual answers I read are something like...
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