Negative Definition and 1000 Threads

hi, does anyone know why vacuum energy has negative pressure? is it only experimental or it is theoretical too? i also wonder if the negative pressure of the Casimir effect is absolutely negative or if it is relatively negative relatively to the rest of the laboratory? i would be...

Are there any negative probability or negative energy photons?

in 2's complement the negative of 1 is "111". but it also signifies 7 in decimal. how does this -ve 1 is differ from 7? thanks

Homework Statement If you dive into the water does it do work on you? Positive or negative? Homework Equations The Attempt at a Solution I think I know this one, it is negative work because he is pushed up from resistance, but continues to go down.

I want to plot a line in mathematica with a negative slope by setting it's starting point, length, and slope but i couldn't figure out how to do it. example: A line "AB" has a starting point (40,0) has a length 10 has an angle 127 degrees between x axisIn MATLAB i can do this with %% k =...

I know that a Schwarzschild metric cannot have negative mass parameter. But what about regions? It is possible to have negative mass parameter between two spherical shells? If not, what is the argument?

Just as the title states, I'm working on a problem and have come to negative infinity divided by infinity. Is this an indeterminate form? I know that if they are both positive it is indeterminate, but I can't remember if one being negative makes a difference.

How can I find probability p that maximized P(Y = y*) when Y has a negative binomial distribution with parameters r (known) and p? I've just reduced the problem with some algebra, but other than guess-and-check I have no rigorous way to solve this problem.

Hello everyone! This is my first post, and I regret that it has to be a question that is so elementary. The Problem: I am in an introductory engineering course in which we were divided into teams and told to construct a catapult. Rather than follow design requirements, and despite my...

Hey people, I searched by this question in the forum but don´t found the answer. I have a simple doubt about this theory in mechanic. The question is: There is negative force? I know that when I am working in math with a vector that represents a force I can use the negative signal to...

Ball launched off a cliff at negative angle... Homework Statement So a ball is launched off a cliff 60 meters high It is thrown at -15 degrees horizontal, and lands 120 meters away. Find the V-initial, V-final, Time in air, and Angle at which it hits the groundHomework Equations inverse...

hi, which phenomena is known in quantum mechanics to cause a negative pressure? as far as I know, the vacuum energy of the time energy uncertainty has a very low energy density but it should have a positive pressure because it pushes and not pulls, am i right? so which phenomena actually...

hi, which phenoma are known in quantum mechanics to cause a repulsive gravity due to negative pressure? as far as i understand, the vacuum energy of the time energy uncertainty has a very low energy density but it should have a positive pressure because it can only push and not pull. am i...

Under what conditions and how will negative oxygen ions react with hydrogen and hydrocarbons (such as methane or gasoline)?Does it require some catalyst or should be burned together? What is a way to harness spare electrons from oxygen when water is formed?

Cant seem to come up with the answer for portion BA car is traveling to the left, which is the negative direction. The direction of travel remains the same throughout this problem. The car's initial speed is 27.2 m/s, and during a 3.90-second interval, it changes to a final speed of (a)39.0 m/s...

Homework Statement There's a 75 kg passenger in an elevator a. what is the passenger's apparent weight when acceleration is zero? b. what is the passengers apparent weight when acceleration is positive? c. what is the passengers apparent weight when acceleration is negative? Homework...

Homework Statement In our lab recently we measured the resistance of copper as a function of length. I plotted a graph with resistance as the dependent variable and length/area as the independent variable. I know the slope of the best fit line is equal to the resistivity of copper and that...

I watched a video there about cathode ray tubes and the guy in the video demonstrated the negative pole of a magnet deflecting the beam and the positive pole attracting the beam. I know that moving electrical charges create magnetic fields but I didn't know their magnetic fields always deflect...

This question is unsourced and hence may be wiped out as hearsay, but perhaps some kind person might answer anyway. I remember (but cannot find the original source) that I once read a speculation that a "particle with negative energy" (not referring to anti-matter, but some sort of exotic...

Homework Statement A car is rolling to the right and you try to slow it down by pushing on it to the left. You are doing A) positive work B) negative work C) no work until the car comes to a stop D) You can’t tell because I didn’t tell you which way was positive. Homework Equations...

If the charge on an isolated conductor is negative, is it's capacitance negative by the formula C = Q / V??

Hello, For a reversible heat engine between temperatures T_1 and T_2, the ratio of heat going in and out the engine is \frac{Q_1}{Q_2} = \frac{T_1}{T_2} (second law). Say T_1 = 200 K and T_2 = 273 K, then heat goes from 2 to 1 and as we can see, the ratio of heat that goes in the engine is...

Why do weights in a weighted average have to be positive?

Hallo I'm new to this (wonderful) forum, and to SR too... I've a general question about the space time interval invariance. Say we have two points A and B, at rest each other, at distance AB. Now A and B simultaneously in their reference frame emit a flash of light. The space time interval...

Homework Statement If 3.00 10-3 kg of gold is deposited on the negative electrode of an electrolytic cell in a period of 2.62 h, what is the current in the cell during that period? Assume the gold ions carry one elementary unit of positive charge. Homework Equations delta Q/delta T...

I'm taking Physics 11 and we're doing a graphing exercise. The graph is Cricket Chirps per minute(as dependent variable) on the Y-Axis versus Degrees Celsius(Independent Variable) Along the x-axis. I've drawn my line of best fit. The exercise asks that I find the y-intercept of the line of...

I think about on this and found a result, e^{i\pi k}=e^{-i\pi k}=-1\Rightarrow i\pi k=ln(-1) a>1 and k=1,2,3... y=(-a)^{i\alpha }\Rightarrow lny=i\alpha ln(-a)=i\alpha (ln(-1)+lna)=i\alpha (i\pi k+lna)\Rightarrow y=e^{-\alpha \pi k}e^{i\alpha \ln{a}} Then \alpha \ln{a}=-\pi...

I was wondering at the remarkable fact that when an atom has an extra electron it is then possible to apply forces to it to accelerate it. What I find remarkable is the fact that even a heavy ion like mercury where the nucleus is many orders of magnitude more massive than the one electron that...

Wikipedia suggests it is possible for some gases to exert negative pressure? 'Most often, gases and liquids are not capable of negative absolute pressure, or even zero pressure...' Is this an error or can some gases exert negative pressure?

If we require that the north is positive number,For example +10Km,South for the negative number,For example -10Km,So, what is the number of 10 km east then? I think there are other neither positive nor negative，Not only 0 is neither positive nor negative . Therefore, a number of absolute...

Reading some QFT in which we are faced with inhomogeneous equation (\partial^\mu \partial_\mu + m^2)\phi(x)=J(x) The solution is given as \phi(x)=\phi^{(+)}_{in}(x)+\phi^{(-)}_{out}(x)+i\int{d^4 x\Delta(x-x')J(x') where \Delta is the appropriate Green's function. "in" means the...

Homework Statement I've got a gap in my understanding of power in circuit. I have a feeling my problem has something to do with sign convention or something. Anyways, here's the question, Two electrical devices are connected at an interface shown below(see figure). Using the reference marks...

Homework Statement lim h->0 [(11+h)^-1 - 11^-1]/h Homework Equations The Attempt at a Solution I made the numerator into two fractions with the denominator h. After combining the fractions in the numerator I was left with 121 when I put in 0 for h.

I know that N (natural numbers) is the set of non-negative integers, 0, 1, 2, 3, 4...infinity, and that Z is the set of all integers, both positive and negative. But what is the name or representation of the set of negative integers?

Hello, I've always heard that when you will jump start a car you connect both cathodes (positive terminal) and you connect the anode of the good battery to the chassis of the stranded car. Why is the setup like this and not connect both negatives with each other too?

Imagine there is a piece of paper negative mass simply pushes up while mass pushes down doesn't that mean that a black hole would be created by mass and negative be same a rip in the paper or in other words space ps I am not very advanced in physics so don't flame me and try to keep your...

i would really appreciate if someone could help me out with this one. i m preparing for an exam and this question is a question from papers of previous years and its bugging me because it seems very specific in that i can't seem to find anything like it in textbooks. what i m mainly stuck on...

i would really appreciate if someone could help me out with this one. i m preparing for an exam and this question is a question from papers of previous years and its bugging me because it seems very specific in that i can't seem to find anything like it in textbooks. what i m mainly stuck on...

In his popular-physics book "The Universe in a Nutshell", Hawking presents the creation/annihilation of virtual particle pairs in two ways: (1) one particle has positive energy, the other negative energy, and (2) a matter/antimatter pair. This leads to the obvious conclusion that he is...

Homework Statement When trying to solve a question about parameter independence of certain aspects of the Jacobian of a real valued function on a manifold I came to the point where I have to show the following: Let A be a matrix, J be the Jacobian of an orthogonal transformation (I suppose we...

Homework Statement Solve for x (1/10)^(x - 1) < (1/10)2. My Dilemma The problem is that using one method will yield one answer, but using another method will yield another. Why is that? Please help. My issue is not regarding the right answer (the right answer is x > 2). It's regarding the...

I have before theoretized about the idea if matter with a negative mass could theoretically exist, and what it's properties would be, acc. to the standard theories (GR). In fact you could argue for two kinds of models for this hypothetical negative mass matter, namely: model-1: anti-symetric...

Homework Statement Given f:A→B and g:B→C, let h=g(f(a)) If h is injective, then g is injective. Give a counter example. Homework Equations Injection: Let f:A→B For all f(x1)=f(x2) implies x1=x2 The Attempt at a Solution f(a)=\sqrt{a} from [0, infinity]→[0,infinity]...

During beta negative decay, in an unstable isotope, a neutron is converted into a proton, electron, and antineutrino. The electron and antineutrino are ejected from the atom and the proton remains in the nucleus to become the new daughter element. For a beta negative decay reaction for some...

Homework Statement Don't need help solving just have a question about the question Rectangle ABCD has vertices C and d on the x-axis and vertices A and B on part of the parabola y = 9 - x^2 that is above the x-axis. a.) Find the coordinates of A, B, C, and D in terms of x. b.) Determine...

I've been toying around with stuff I probably shouldn't be. :biggrin: I've been sketching a graph of y=x^n where n is a rational number (as opposed to an integer). Of course, when I get into the fractional exponents, the negative portion of the curve ends up being imaginary (eg. x=-2,n=2.5...

This is just a little question to satisfy my own curiosity, but can the Negative Ion of an Oxygen atom/molecule be used as an oxidizer? I would think not, because it wouldn't be able to accept another electron if it already has one. Am I right?

This theory just dawned upon as i feel asleep- In the same sense matter bends spacetime fabric to create the force of gravity (matter and light are attracted to it), is it possible for spacetime fabric to be inverted, so matter and light flow (repel) away from this 'negative gravity'? Instead...

Homework Statement Problematic Part of the problem: Consider a negative ion beam of He- ions. The given beam characteristics are the beam energy (E) and the beam current (I0). An electrostatic chopper is placed on the beam line, which pulses the DC beam with a pulse width of say t_1...

hi i know this is kind of a basic question..but what in reality does a negative absorbance reading means?? why can't the spectrometer just say its out the reading range or something?? does a negative reading really say something can we look at it and detect something...like if the negative...