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

    Can Negative Mass Really Defy Gravity?

    Michio Kaku mentions in his TV series "Physics of the Impossible" about negative mass being able to repel gravity. I haven't heard much about this before. How would the negative mass affects the geodesic in spacetime manifold? Perhaps by causing negative curvature of spacetime? Would this...
  2. B

    Negative Acceleration: Deceleration or Reversal?

    in acceleration time graph when the acceleration is constant. Then at an instant it has negative acceleration. Does this mean that the body is decelerating or it is accelerating in the opposite direction. eg. http://hyperphysics.phy-astr.gsu.edu/hbase/mechanics/motgraph.html {last graph}
  3. K

    Can the total change in entropy be negative value?

    actually i have worked out the question..but i doubt about my answer..can anyone help me to verify this question please..kindly please refer to the attached files whereby i attached questions as well as my workings also...i really need help please..thanks in advance ..if possible may i have the...
  4. S

    Basic Question: Positive and Negative Electrical Charge

    I am not a student of Physics. I want to know. I am curious. I never understood a basic thing. What is the difference between a positive and a negative electrical charge? What characteristics describe the two charges? Are they just something you mug up as a given example of the duality in the...
  5. G

    Why do negative numbers behave the way they do in arithmetic?

    I am having an issue with why negative numbers work the way they work. For instance why does 5 - (-2) = 7 Why do two negatives make a positive when you subtract them? For me that equation reads 5 apples and you take away -2 apples which to me doesn't really make sense because in real...
  6. H

    Two port impedance, negative inductance?

    Hi I'm doing simulations in preparation for experimental measurements of decoupling capacitor parasitic inductance. I've done simulations of two port measurements, in mentors hyperlynx, of parallel capacitors on small power planes. These have given me s2p files that I've converted to...
  7. J

    Torus and sphere with positive or negative curvature

    Hi I know that the sphere has positive curvature everywhere, and the torus has positive an negative curvature. Is there a space homeomorphic to the sphere such that this space has negative curvature everywhere? And, is there a space homeomorphic to the torus such that the curvature is always...
  8. S

    Maximum principle - don't understand why RHS is negative.

    Homework Statement Consider the linear inhomogeneous second order two point BVP; -a(x)u''(x) + b(x)u'(x) = f(x) for 0 < x < 1 for some functions a, f, b where a(x) > 0 for all x 1) If f(x) < 0 for x = [0,1], show that u(x) attains its maximum value at one of the two end points x = 0, 1. -...
  9. T

    Answear to magnitude of an object slowing to a halt? negative or positive?

    I have calculated magnitude of acceleration of an object slowing to a stop to be: -5.1m s^-1. I then had to find the magnitude of the unbalnced force applied to the object for it to stop which i found to be: So F= 1500 kg * 5.1 m s^-2 Which equals 7650kg m s^-2 Which...
  10. R

    Confusion regarding negative resistance circuits

    Hello Everyone! I have recently been attempting to understand negative resistance circuits(on a practical level at least to start). I've pulled up a few websites giving actual circuits to demonstrate the principle, but still can't quite understand it. Every circuit example so far shows either...
  11. O

    What difference is between Beta particle and negative charges?

    "Beta particles are high-energy, high-speed electrons or positrons emitted by certain types of radioactive nuclei such as potassium-40. The beta particles emitted are a form of ionizing radiation also known as beta rays. " Negative charges also contain electrons, Beta particle are...
  12. F

    Looking for fortran subroutine for I Bessel function with negative order

    Hello all, I am developing a new analytical solution for a problem in flow in porous media, and I need to write it in Fortran. This solution contains the modified Bessel function of the first kind, I_n(x). The order n is a real number, and it can be both negative and positive. The argument x...
  13. K

    Why is the Gravitational Potential Energy formula negative?

    Hey guys So if I lift a book from the ground it gains potential energy. I do work on the book and when I release it the potential energy that I gave the book pulls the book back down to Earth. However I was looking at a potential energy formula for planets which was V = -GMm/r But...
  14. T

    Can angles be negative in coordinate geometry?

    Homework Statement Can you have a negative angle, or do you just assume absolute numbers? Your coach tells you to turn south for 10.0m and then turn and run east 15.0m. How far must the ball be thrown from where you started to where you ended? Homework Equations a^2 + b^2 = c^2...
  15. T

    Positive vs. negative work in an elevator?

    Homework Statement You are moving into an apartment and take the elevator to the 6th floor. Does the force exerted on you by the elevator do positive or negative work when the elevator (a) goes up and (b) goes down? Explain your answers. Suppose your weight is 685N and that of your...
  16. A

    Negative value when calculating the distance

    A 1000 kg car traveling rightward at 25 m/s slams on the breaks and skids to a stop (with locked wheels). Find the distance required to stop it. Coefficient of friction between the tires and the road is 0.95. Let g=9.8 m/s^2 Solution: 2aΔx=vf2- vo2 a=µg 2 µg Δx=vf2- vo2 vf=0 2 µg Δx=-...
  17. H

    Negative Tension: Myth or Reality?

    Is there anything such as negative tension?
  18. jaketodd

    Overall, H2O More Negative Than Positive?

    There is a link to a picture below. It shows two Hydrogen atoms on the same side of an Oxygen atom (both on the lower half of the Oxygen atom). Because the distribution of Hydrogen in H2O is not symmetrical, does that mean that, on average, the H2O molecule is more negatively charged in its...
  19. A

    Negative value of displacement

    A car traveling rightward slams on the breaks and skids to a stop (with locked wheels). Find the distance required to stop it. (I have taken away some parts of the question.) The answer became -33.6 m. Why is the value negative? Thank you in advance!
  20. L

    Should I take the absolute value of a negative t-test statistic?

    I have calculated the one sided t-test statistic and am getting a negative value as the sample mean is less than the mean under H_0. there are no negative t values in the table - do i take the absolute value of this? thanks
  21. B

    Matrix equation: Ax=b; can A coefficients be negative? Or could this be error?

    Hello all: I'm using a code for solving partial differential equations that describe transient advection and diffusion. I'm more of a chemistry person, so I'm a bit lost on some of the basics of the calculation method. A general question: As my calculation progresses, I see that...
  22. B

    Is Feedback Resistors' Impact on Transistor Amplification Significant?

    Well, this post was just calling me out. So my past few posts about transistors, and very good people that replied them, told me that I should embrace this new concept of feedback. We just learned it last week, and I wasn't so excited about it.(meh, just another technique to make transistors...
  23. C

    Engineering Electric circuit with negative reference voltages and diodes

    Hi I am having trouble figuring out what to do with negative reference voltages in my circuit. I attached my problem(Problem 3) and I know that some current will be drawn out of the ground and I think all of the diodes will be on but I am unsure how to approach this problem.
  24. A

    Why is potential energy the NEGATIVE of the work done?

    Why is the change in potential energy the NEGATIVE of the work done by a force? What is the negative sign doing there, and what physical meaning does it serve? Any input is appreciated, but a rather detailed explanation would be great, as I am having much difficulty understanding this.
  25. T

    Negative and positive results when dealing with Newton's Laws

    I think it's a pretty simple question. Let's say we're talking about a moving elevator in which a person stands on a digital balance. The textbook tells me to treat the downward direction as positive, so the value of acceleration is 9.8 m/s^2 instead of -9.8m/s^2 I'm asked to find out the...
  26. L

    What is really meant by negative voltage?

    Hi, I get confused when I look at the dual power supply. I wish I can add two capacitor bank at both +ve and -ve terminals to improve its regulations. If I connect the capacitor bank, maybe 0.1F directly to the supply line, there must be a sudden high current flow through the rectifier...
  27. A

    SHM- Problem with negative signs

    I have problems understanding the use of negative signs in SHM. ie. mx''=-kx Why is there a negative sign for the constant k and what does the negative sign mean?
  28. W

    Leyden Jar - 2 bottles - 1 positive 1 negative?

    I never could get leyden jars to work. I'm trying to use a few 3 liter bottles I have here at home. I also have quite a few solar panels and other materials like aluminum foil and copper. I was thinking today that it seems it would be easier to have 2 bottles, 1 with a copper lead dipping...
  29. L

    Negative ions effect benefit on the body ?

    Negative ions effect benefit on the body ? I saw many claim on the internet by company selling bracelet, necklace and insole that emit negative ion using volcanic ash,tourmaline or a mixture of many mineral. They claim negative ion research stating increase energy, deeper sleep, more...
  30. L

    How does tourmaline produce negative ions ?

    How does tourmaline produce negative ions ? Where those negative ions come from ? I know that negative ions is simply atoms with 1 extra electron so where they come from ? I also know that volcanic ash also produce negative ion same question ?
  31. S

    Negative Binomial and Chi-square

    can anyone help me with this question :
  32. L

    How does tourmaline produce negative ion ?

    How does tourmaline produce negative ions ? Where those negative ions come from ? I know that negative ions is simply atoms with 1 extra electron so where they come from ? I also know that volcanic ash also produce negative ion same question ?
  33. teroenza

    Experimental negative work function?

    Homework Statement I have experimentally determined the work function from the intercepts of a fit line in graph of stopping potential (J) versus frequency (Hz). This is from a photoelectric effect lab. The value of the intercept, which I believe is that of the work function, is returned as...
  34. S

    Negative Binomial random variable

    Data is collected on the number of fish caught per day on a month long fishing expedition. It is hypothesised that the data are consistent with a negative Binomial random variable ,X , starting at 0, so that X~Neg Bin(k,p) where E[X]=k(1-p)/p and Var =k(1-p)/p^2 . However, before a hypothesis...
  35. B

    Exploiting Directions of Negative Curvature

    The title of an old paper... It mentions that in order to use the full information of a hessian in 2nd order optimization that you should make a part of your iterative step to include v (eigenvector corresponding to smallest eigenvalue, assuming that the eigenvalue is negative). By doing the...
  36. L

    Negative Work function in Photo electric effect

    Homework Statement In my attachment, the x intercept gives threshold frequency and the y intercept gives the work function. Homework Equations The Attempt at a Solution Work function is the minimum energy needed to pull out an electron from the metal surface. My question is, from...
  37. P

    How do you konw if dipole movement is negative or positive?

    Let's say you have 2 charges of magnitude 2C except 1 is + and the other -. They're separated by 2m. dipole moment=p=qL Which q do you plug in there?
  38. S

    Can Vectors with an angle 180(degrees+) have a negative magnitude?

    Homework Statement Can vectors with 180+(degrees) have a negative magnitude? I'm trying to find components of a vector that is going 260 km, 48 (degrees) south of east. So I'm confused whether the 260 is positive or not because of the -48 degrees.Homework Equations (\vec{V}) (sin\theta)...
  39. P

    Is e field equal to the negative derivative of electric potential?

    Since V is the integral of -E. Shouldn't E be derivative of -V. I asked my TA that and he said something about them not having that kind of a relationship, can someone explain this?
  40. G

    Negative duct fitting coeffecient

    In the ASHRAE fitting database, there are negative duct fitting coefficients. I assume this means that that particular fitting will produce a pressure regain. However, I am unsure that it would be a static regain because: the formula is P(total)=C*P(velocity), and P(total) only can only drop...
  41. P

    Negative absorption peak in FTIR

    What does it mean if one found negative absorption in uv-vis absorption graph?
  42. G

    Negative sign in coulomb's law/centripetal motion question

    Homework Statement I had a question in my physics class today that was relatively easy but what I was confused about was a misplaced negative sign. "An electron is rotating around a proton at a distance R. The mass of the electron is me and the charge is -e. Find the period." Homework...
  43. Useful nucleus

    Negative formation energy of a point defect in a solid

    It is very common to see in the literature negative formation energies reported for point defects in solids using different simulation techniques ranging from Density Function Theory to Molecular Dynamics. The authors rarely comment on what does that mean physically. I will mention here two...
  44. Jadaav

    Is zero positive or negative ?

    Is Zero a positive or negative whole number ? Is it even a whole number ?
  45. M

    Finding the energy field due to three positive point charges on a 4th negative charge

    Homework Statement Three equal positive point charge of magnitude Q=7.00uC are located at three corners of a square of edge length d=4.8cm. A negative charge of -21.00uC is placed on the fourth corner. A) At the position of the negative charge, what is the magnitude of the electric field due...
  46. A

    What Does Negative Time Indicate in Particle Motion Analysis?

    So my initial thought was that there's no such thing as negative time. Obviously, however, that's not the correct answer, because let's face it; the question can't be that easy. The question could have started with just the velocity equation and asked us to find the meaning behind the negative...
  47. G

    What does negative acceleration really mean?

    I've read that negative acceleration can mean two things: 1) Something is slowing down 2) Something is speeding up in the opposite direction Can it mean those two things at the same time? So, if I'm driving a car at 30 mph, and then I slow down... how is it that the car is speeding up in the...
  48. C

    Convergent series with non-negative terms, a counter-example with negative terms

    Homework Statement The terms of convergent series \sum_{n=1}^\inftya_n are non-negative. Let m_n = max{a_n, a_{n+1}}, n = 1,2,... Prove that \sum_{n=1}^\inftym_n converges. Show with a counter-example that the claim above doesn't necessarily hold if the assumption a_n\geq0 for all...
  49. H

    Why must vertical acceleration always be negative on projectile motion?

    y= y_0 + v_(y0)t - 1/2gt^2 why is it -1/2 gt^2? what if somebody was to throw ball downward? is that still negative velocity? wait, does negative in velocity mean direction?? or slowing down kind of confused while writing this question if it is direction why is it negative for...
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