Negative Definition and 1000 Threads

We have a variable-inertia flywheel coupled by a shaft to a fixed inertia flywheel. The VIF (variable-inertia flywheel) has a moment of inertia range of 10 to 5 (m2*kg) and an initial velocity of 100 (rad/s). The fixed inertia flywheel (fw) has a MI (moment of inertia) of 10. The initial...

What happens if you combine both negative and positive feedback in one opAmp? assuming you only have unity gain in the negative configuration and no capacitors? I reckon adding capacitors would add some oscillatory behavior but would that be the case if both configurations are made only of...

Negative frequencies in spectrum analysis... Hello everyone... When we do the frequency analysis of a signal using Fourier transform, we get spectrum at negative frequencies also. What are they and what is the physical significance of such frequencies? Its hard for me to imagine a negative...

Homework Statement I have the matrix A = [-10 3.5 3; 3.5 -4 0.75; 3 0.75 -0.75] I need to determine whether this is negative semidefinite. Homework Equations The Attempt at a Solution 1st order principal minors: -10 -4 -0.75 2nd order principal minors: 2.75 -1.5...

I've heard it said that relativity formally permits tachyons and that we don't believe they exist merely because there is no empirical evidence of them. However, since a tachyon's speed exceeds c, its γ must be imaginary. The t-component of the particle's 4-velocity is, depending on...

Hello PF people, Homework Statement In a Compton scattering event, after the collision, the Photon has an energy of 0.12 MeV and the Electron has an energy of 0.04 MeV. Find the following: i) The Wavelength of the photon before the collision. ii) The scattering angle for the photon...

I will write a program about principle bernoulli, but i have a problem. My input data: Pressure(p1) = 1000 Cross-section(A1) = 1 Velocity(V1) = 1 Cross-section(A2) = 0.5 Velocity(v2)= (V1A1)/A2 to simplify: h1=h2 i'm counting the pressure p2 : p2 = p1 + 0.5*v1*v1 - 0.5*v2*v2...

Ok, I am starting to understand what voltage is. But I'm sort of confused when it comes to negative voltage. I know that voltage is defined as potential energy per unit charge. I understand it as analogous to "pressure". I don't understand what it means to have negative voltage though. How can...

At what amounts can negative energy be produced by the Casimir effect? I know these are very small, but I am curious to know how small.

is clausius inequality correct for negative temperature?, if you see the proof of it in positive temperature its not correct.

In statistical mechanics and kinetic theory,it is shown that temperature can be interpreted as a measure of the energy of particles.But such an interpretation seems to need refinement because of introduction of negative absolute temperatures. Can we still interpret temperature as a quantity...

we know the entropy in each process increases is it true for absolute negative temperature?

The facing surfaces of two large parallel conducting plates separated by 10.0 cm have uniform surface charge densities that are equal in magnitude but opposite in sign. The difference in potential between the plates is 500 V. An electron is released from rest next to the negatively charged...

what's negative frequency? can we say s=-3 in example bode plot ! or we can say it's unstable at w=-3 rad/s that's I mean is there negative frequency??

Why wasn't the electron fixed with the 'positive' value? wouldn't that simplify a lot of issues with electronics problems, i mean, that way things wouldn't have to be all backwards. like, wherever the electrons go is becoming more negative, and whichever direction they are leaving is more...

I am making a proposal that the United State abandons its current tax code and adopts the Negative Income Tax as its federal tax model. For those who don't know the Negative Income Tax would annually tax every person at the same percentage and it would give a tax deduction/reimbursement of the...

Hello, my question is in the context of modeling static neutron stars via the TOV equation. This is for a 20 week research project for my undergraduate degree. I am creating different equations of state to relate energy density to pressure, I have already used ideal fermi gas models, and now...

Thank you for any help you are able to provide. I myself think that the electrons will flow to the human body and further drain the battery.

For instance, say I have -ln(-∞) Does the negative sign on the natural log cancel with the negative sign on the infinity? Is this true? -ln(-∞) = ln(∞) Thank you -Drc

Homework Statement Two half-rings of charge of opposite polarity are brought together at the origin (so that the rings create a full circle against the y- and z-axis. Each half-ring has a charge of magnitude Q and radius a. Derive the net electric field at point P, located on the +x axis a...

Homework Statement I have a transfer function: H(jw) = RCjwz / (1+RCjwp) and I'm being asked to find R, if C = 47nF and the desired pole frequency is at 3.3kHz. what I'm confused about is that the pole frequency is supposed to make the denominator of the transfer function 0, but...

I attached the circuit. I did kirkoff's voltage law (assuming current goes clockwise): -15+5-10,000I-40000I=0 where I=current I=-2*10^-4 A V_out=40,000*-2*10^-4A = -8V The way V_out is shown, it should solve to be negative, correct?

In plane wave elliptical polarization, the book said if the Ellipticity angle is possitive, it is a Left Hand Circular polarization(LHC). If Ellipticity angle is negative, it is Right Hand Circular polarization(RHC). My question is how can Ellipticity angle be negative...

The speed of car A is 72.2 km/h while the speed of car B is 53 km/h. If car B is now 48 km ahead of car A, how much time is needed for car A to catch up with car B? car A let x = the current position of car A speed = 72.2 km/h time = x/72.2 hours car B let x + 48 = the current...

I am trying to find the sky position of asteroids so that I can observe them using a telescope. This site quotes the declination angle in hours and appears to range from 0 to -24. I have never heard of a declination angle more negative than -12 hours. What does this mean...

What happens to the Reimann tensor at the event horizon of a black hole? Do some of the 24 components become zero or infinite? What happens to parallel transport of a vector on the surface of an event horizon that is different than on a surface outside the event horizon? I'm newly educated...

“The inverted Boltzmann distribution is the hallmark of negative absolute temperature; and this is what we have achieved,” says Ulrich Schneider. “Yet the gas is not colder than zero kelvin, but hotter,” as the physicist explains: “It is even hotter than at any positive temperature – the...

"Negative Temperature" Achieved I was reading this article which says that scientists have recently achieved a "negative temperature" system, which apparently has a temperature which is "below absolute zero"...

"Negative temperatures", BELOW 0 Kelvin?--Confirmation please Someone shared this article with me: http://www.huffingtonpost.com/2013/01/04/absolute-zero-record-setting-negative-temperature_n_2404666.html ...And I've seen a couple others apparently referencing the same thing. If it's a...

Chemistry student saying hi to everyone Just read http://www.nature.com/news/quantum-gas-goes-below-absolute-zero-1.12146 about negative temperature. I knew I wouldn't understand a single sentence of the actual Science paper, but I took a look at the Science perspective (Lincoln D. Carr) but...

Homework Statement What is the limit of e^x when x approaches zero from negative side Homework Equations The Attempt at a Solution Taylor series? Then the answer is put all x= 0 , and the answer is 1, but why the question ask from negative side?? Thank you very much

Homework Statement Say we have a 2D rigid body transform, with parameters p = [ p_1,p_2,p_3] for rotation, x translation and y translation respectively. I'm using the transform to .. transform an image. Is there a way to have: For a point x , y : x',y' = transform(x,y,p) <=> x,y =...

What are negative numbers? Have you even seen a negative number of chickens? i haven't. The idea is merely an abstraction of subtraction. An abstract idea doesn't have to have any physical significance at all, even if the idea was derived from physical things.

in Fourier transforms of normal baseband sigal , spectral components are replicated on both +ve and -ve sides of frequency axis. i know that both -ve and +ve frequency components contribute to the total power of the signal but i don't know the physical significance of the -ve frequencies...

...plate of a different capacitor, why won't the positive end of a battery (lets say AA) pass current to the negative plate of a different AA battery. Does it have something to do with the chemical reaction that happens inside the battery?

When my book deals with bound states and scattering states it puts: E<0 bound state, E>0 scattering state. What reference for the potential have been used for these?

Hi! So, when we're calculating the potential energy of a mass in space we make it negative because we assign infinity as the reference point. Now, to find the potential energy of something I understand that we find the work that is done to it to move it from the reference point to another...

Current theory of the big bang postulates that there was a very period when gravity reversed and the result was what we term the 'big bang'. Assuming this to be true, negative gravity would cause time to be a function of i. -- 1/2 A = D / (T x T) If A is negative then either D or T...

Does a di/dt<0 mean an increasing current moving from a lower potential to a higher potential (if we define the direction of current to be the flow of the positive charges)? Similar question with negative current i.e.; dq/dt<0.

I am studying Physics Vol2 by halliday, resnick and krane. I was attempting the coloumb force exercises..If we put one charge negative and other positive in the formula..then the force comes out to be negative but the instructor manual for the book ignores the negative charge, and take it as...

Homework Statement If I have a Hamiltonian matrix, \mathcal{H}, that only depends on a kinetic energy operator, do the energy eigenvalues have to be non-negative? I have an \mathcal{H} like this, and some of its eigenvalues are negative, so I was wondering if they have any physical...

Homework Statement How come A person picks a 1.00-kg box of macaroni from off the shelf and lowers it 0.77 m into a shopping cart. The work done on the macaroni by the person is negative work however when person picks up a 1.00-kg box of macaroni from off the shelf and lowers it 0.77 m into a...

Homework Statement d=1352846320 The question asks for fxy. The rate of change of (the rate of change of f in the x direction) in the y-direction. We know fx is negative because as f moves in the x-direction, f decreases. But how do I know the rate of change of fx in the...

My advanced statistical mechanics prof told me that it wouldn't make any physical sense to allow N (the number of particles in a system) to be negative. But, somehow, I think that this possibility should be theoretically left open; perhaps there are some systems whose statistical behavior would...

Homework Statement What is the exact definition of negative feedback? the instructor told us that negative exists if the output is connected back to the inverting input through a passive element. But what exactly is precise the definition ? (say parallel connect, same two nodes, I want the...

[SIZE="4"]we already know that the scalar component of the Centripetal ( Radial ) Acceleration vector is always negative because it's ALWAYS directed to the opposite direction of its unit vector ( toward the center of the circle ) , and this is satisfying to me and to the formula . however ...

Im completing Engineering Maths cover to cover in an attempt to get more familiar with maths as I finished my education many years ago without really understanding many basic maths concepts. This problem is at the back of the introduction to algebra. (x-2y)^2 - (2x - y)^2 Now I can expand...

If a universe existed where all the mass was negative but everything else was the same as our universe in terms laws of physics what would happen? To be more specific it appears that all the mass would repel each other, would negative mass atoms form, would these particles absorb or emit light...

lim x( (x2 −2x+5)^(1/2)−|x−1|) x→−∞ so far, the only way I have started the question is by multiplying for the conjugate but i cannot get it to simply to the answer which is -2 after that step.

Homework Statement How much work is done by the electric field in moving a particle from (a,a,0) to (a,a,a) in a region where the electric field is: E = zye_x + yxey + xyezHomework Equations F=qE W = integral F dot dl V(2)-V(1)= - integral E dot dl The Attempt at a Solution I know how to do...