Negative Definition and 1000 Threads

Can a charge, brought into a chargeless world filled with some geometry of conductors and dielectrics, induce a negative potential anywhere in that world? I feel the answer is no. But I cannot think of a good way to prove it, or even attack the problem. More explicitly, imagine a world...

Hi yall, Im trying to understand waves and I am wondering why the velocities are negative sometimes and or positive. I think that the velocities are negative because of the slope of the wave as it is coming down? I just want to completely understand it and am a little confused. Like...

Hi, I am a student who's learning about quantum mechanics. I was reading about the RTD (Resonant tunneling diode) and I got the general idea. However, I was looking at a I vs V graph and came up with a question. Since Resistance = V/I, the inverse slope of the I vs V graph has to be the...

Homework Statement How much positive and negative charge are in a 50g Tungsten ring? Homework Equations Standard atomic weight 183.84 The Attempt at a Solution

I'm just learning but I can almost SWEAR that this is right, just reassure me?

From Wikipedia: "Positron emission or beta plus decay (β+ decay) is a type of beta decay in which a proton is converted, via the weak force, to a neutron, releasing a positron (the antimatter counterpart of an electron) and a neutrino. Isotopes which undergo this decay and thereby emit...

Might be a naive question. In many places, specially in the Hubbard model, people use a minus sign before the tight-binding hopping amplitude. What does the negative sign signify for? Any special intention? Thanks.

What am I finding to be confusing.. The graphs of Millikan's data were straight lines with equal slopes. The graph was plotted maimum kinetic energy (eV) versus the frequency of the wave. This was the graph that produced the linear relationship from the photoelectric effect. What does it mean...

can somebody simply explain what is meant by NEGATIVE QUANTUM STATES , as given by dirac in his theory?i know its not as SIMPLE as i want it to be , but still I would like to know its significance in the most basic way!

Hello everyone. I understand the concept of work in general, but the concept of negative work still somewhat baffles me. One of my main problems is this: according to my textbook, 3 conditions must be met in order for work to be done, and one of them is "at least part of the force must be in...

Sometimes to understand things I need to come up with ideas and have them shot down. This is what I am doing here. I have been informed that the Cashmeir effect may not be due to negative energy so I have an idea for an additional experiment. Suppose we were to make a "box" with little...

Hi PF, just a quick question that always seems to confuse me.. when should 'g' be negative in equations? Intuitively, I tend to always substitute -9.81 m/s into equations but it seems that this can be incorrect in special cases. Are there certain situations where 'g' should be or shouldn't be...

what is mass? and is negative matter really possible i wasnt sure if i should post it in this forum or not but i thought the second part of the title refers to particle physics so i posted this here. so as the title suggests i was wondering what is mass. i have heard answeres like it is a...

Hi, nice forum. I was thinking how I would go about proving with an example, that negative Gs are occurring? Homework Statement Say a stunt pilot is doing a maneuver that will expose him to negative Gs. It could look like this...

Circuit can supply "negative voltages"? I read an article trying to understand voltage dividers better. I then read this quote that threw me off! Now, what does it mean that a circuit is designed to supply both positive and negative voltages? I'm pretty new to electricity. All I need is...

The negative pressure generated in the Cashmeir effect suggest that negative energy can exist in small spaces between non-conducting plates. How much negative energy exist in a given amount of space as measured in units that refer to energy (as opposed to units of force created by the Cashmeir...

I was just reading a book on low-temperature physics and stumbled upon a graph that shows the energy of liquid Helium-4 in relation to its molar volume. The graph includes both zero-point energy and the potential energy of the liquid, and the latter goes steeply (basically a vertical line) from...

How to divide positive and negative charges from each other without them interacting with other matter or charge patterns. ,please answer I only need this to make my ultimate machine

solve for x: x^-2 = 1/9 solve for x: x^-2 - 13x^-1 +36 = 0 I don't understand how to solve either equations.

Getting Rid of Negative Exponent! Homework Statement So I am solving a Diff Eq ( separable equation) and I am down the the last step. After integrating both sives and solving for y I am left with y^(-2) on the left hand side. How do I finalize it and get rid of negative 2 expononent...

2 parts: 1. What does it mean if you get a negative gauge pressure value when calculating from manometer containing compound liquid? When calculating absolute pressure how does atmospheric pressure affect this negative pressure ie. atmospheric pressure opposes the direction of force? 2...

i am only a year 11 student so i don't know much about the Theory of relativity i just heard that if we can travel at the speed of light our time will be slower than the other so i am just wondering if we can travel at a negative speed of light that means that we can go back in time?

I've heard about this over and over again, but i don't how this(negative pd) can be achieved in an electric circuit.

Hi, I am trying to estimate variance for negative Binomial distribution using maximum likelihood estimation and Expected (Fisher's) information to determine its variance. I know what variance is for this distrubution but I cannot derive it. Here is my solution. Any comments and...

Why is int(1/(1-x))=-ln(abs(1-x))? If you substitute u=1-x then int(u)=ln(abs(u))=ln(abs(1-x)) Also, in this question you're trying to find the particular solution y=f(x) to the given differential euqation with initial conditions f(-1)=2 dy/dx=6x^2-x^2y d^2y/dx^2=-12. So i get to...

Let's say that negative mass existed, what might it look like? Could it look like an ordinary rock stuck in the ground? If so, what would happen if you tried to move it around? If it moves in the opposite direction it is push then wouldn't it be impossible to move it in any direction? Would it...

Hello Everyone, My statistics is terribly rusty so I am turning to all of you for assistance! I am in the process of reviewing my old text but I figured this may be quite a bit quicker. Homework Statement Suppose "x" is normally distributed with "mu_1" and "sigma_1." Now suppose x is measured...

Gamma Function on negative Fractions! If we take a look at the Gamma Function and evaluate the integral by parts then we will get infinity in the first step of Integration by Parts eg: Integral e^-1*x^-5/3 Limits being 0 to Infinity as usual! If we try to integrate this we will get...

The Klein Paradox is the name given to the following prediction of Klein Gordon's equations. If you send a current of electrons against a potential barrier of height V such that the energy of the incident electrons is less then V - m, you should observe a current of positrons coming out of the...

Homework Statement I am working with cosmology and expansion. Obtain dz/dt as a function of z and H_o only. What is the sign for dz/dt and why? z is the redshift and H_o is the Hubble constant. Homework Equations The Attempt at a Solution So I found the equation for dz/dt =...

What's the proof for a negative number times another negative number gives a positive number? Thank you

I would appreciate some clarification on working with lenses and virtual objects (when the object distance do is negative). I'm not sure what happens when the do is negative and you get a positive value for di. On which side of the lens does the image go? Normally, for a lens, if di is...

as we know at zero degree temp. water condense to form ice. so what will be the relative humidity of a chamber at a temperature below zero degree temp.? will it be nagative or what?

what are the restrictions (if any) on y=1/x^(-2)? is it equal to just x^2 so no restrictions or what it is have hole at x=0? or do you change too all positive exponents before looking at restrictions? what exactly are the exponents rules that govern this stuff so confused

Hello Forum, maybe not a new topic but let me ask anyway. The voltmeter is a simple device used to measure voltage or potential difference. Take a 9 Volt battery. If we connect it to a voltmeter the reading could be either +9 V or - 9 V. What makes one of the leads of voltmeter different...

Hello All! I have a question about negative switching for a capacitor dump circuit. Currently we are dumping a capacitor to 3 12VDC battery on the negative leg. We are using an SCR, 5.1V zener and two 3.2V LEDS. The capacitor is a 75V, 17,000 uF computer grade cap. The capacitor charges...

1. The Problem: An elevator is hoisted by its cables at a constant speed is the total work zero, negative, or positive? 2. Homework Equations : g= -9.81m/s2 3. The Attempt at a Solution I'm thinking that since the weight of the elevator is in downward direction along with the acceleration of...

I have two physics books that state that U(r) = -GMm/r What I don't understand,is how can potential energy be negative? I've done the integral of GMm/r^2 from infinity to r, but I don't quite get the concept of negative potential energy. I don't understand why using r=infinity as...

Homework Statement So, I have a cylinder with radius r and length L and it's filled with water that has a variable height H. I'm supposed to find a formula for the volume of the water contained in the cylinder in terms of H r and L. 3. Attempt at a solution using a circle moved up on...

Hi, If you look at the Schwarzschild geodesics for negative mass, I believe that radial null rays can hit the naked singularity in finite value of affine parameter? but if L <>0 then the null rays get repelled away from r=0 no matter what their energy? does this mean the spacetime is null...

So i need to show if a matrix is positive definite or negative or neither I have a matrix 3x3 A so i compute xTAx I am left with an quadratic equation interms of x_1 x_2 and x_3 The Matrix is of the form A = [ 9 -1 2] |-1 7 -3| [2 -3 3] and solving xTAx i get...

Trying to find out the kinetic energy that a 1kg ball gives the Earth if dropped from 100 ft. I just don't know how to square a negative exponent. 4x10^-24 squared is? I was thinking it would be 4x10^-48, but I really don't know. If that is correct, would the result be different if the exponent...

As you can't take the square root of a negative number without introducing complex numbers, which would be the correct answer to this function: Equation: x = -2 f(x) = √x / (x(x-1)) Answer a) 1.41i / 6 or Answer b) 0

I have a process that a scalar and a photon at the final state. When we take the complex conjugate and sum over photon final polarization state...it give negative sign in the differential cross section...what does this mean? the trace didn't give negative value. M=M^{\mu}\cdot\epsilon_{\nu}...

In my Physics class tonight (Physics for Scientists and Engineers 2), we have a quiz about the following topic: "Where to place a negative charge between two positive charges so that the negative charge has an equal force with each of the positive charges." I was hoping that someone could...

Could anyone please tell me which is right and why. A person lifts 80pounds or 80% of his RM {one repetition maximum lift} for the last 40% of the concentric lift, the weight decelerates. Which or can both of these be deceleration and why please. 1, His RM = 100 pounds, so for the...

When, let's say, a cylinder is rolling on a plane, and there is a rope coiled around the cylinder and the rope moves at an acceleration of A(rope) at the upper part of the cylinder to the right. Ok, so when I try to envision it, the cylinder is rolling in the CW direction. so R(alpha)= -...

I've done an experiment lately on the NACA-0012 and I've found that as the angle of attack increases, the moment becomes more negative. I wanted to know what does that negative value say about the characteristics of the airfoil, and what is its importance. If someone could help me out, this...

Homework Statement Linearize the equation y = Ae^{-\frac{b}{2m}t}, so that lny is the x variable and t is the y-variable. What happens to the slope and the intercept if you increase b? The Attempt at a Solution Taking ln of both sides, I get the equation t = -\frac{2m}{b} \ln y +...

Homework Statement Alright, so I just want some clarification on direct variation, since it seems that every internet source I can find is (seemingly to me) wrong. To me, direct variation means that the ratio of y to x is fixed with y=kx where k is the constant of proportionality...