Negative Definition and 1000 Threads

I am a bit confused. My teacher solved this problem and his answer for the thermal energy produced was -147,000J. My book says it is 147000J. My teacher used the equation K2+P2=K1+P1+Wnc and my book used K1+P1=K2+P2+Wnc. Which one is it?

No.

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

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?

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...

dy/dx = 3px^2 - m Where do I go from here please?

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...

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...

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...

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'}...

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...

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

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...

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...

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 <...

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...

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...

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...

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...

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...

[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?

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...

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...

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...

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...

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...

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...

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...

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...

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

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

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...

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.

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...

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...

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...

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...

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...

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...

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...

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...

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

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...

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...

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...

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!

##\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}##