Negative Definition and 1000 Threads

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...

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=-...

Is there anything such as negative tension?

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...

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!

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

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...

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...

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.

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.

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...

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?

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...

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...

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 ?

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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 ?

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...

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...

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...

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...

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?

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)...

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?

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...

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

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...

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...

Is Zero a positive or negative whole number ? Is it even a whole number ?

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...

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...

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...

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...

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...

I'm assuming that the observer witnesses all other particles enter a horizon, be it an event horizon or the particle horizon. Thus the observer's observable universe would contain himself only. Is this understanding correct and can it happen in finite time? Also does such a universe have time...

How Does Reflection Behave In Arbitrary Surfaces Hi I am interested to know how reflection would behave in a mirror on a surface of negative [gaussian] curvature. I tried googleing it and found nothing useful Thanks Edit: Reflection in a sphere behaves like inversion in a sphere...

Identify which of the ff. object will be positive or negative charge 1) Hand and Hair 2) PVC and Tetlon 3) Glass and Poly ester 4) Rubber and rubber 5) Hand and wood

What is positive and negative eigenspaces? Can you recommend me a referance to know them?

Hello All I'm new to the forum and have a question. I was looking at the time dilation function and noticed that negative time would be described with imaginary numbers and be a kind of anti-time, albeit that rest mass can not be pushed faster than the speed of light but for the sake of...

https://www.youtube.com/watch?v=jERhPMzqSaE http://www.cnbc.com/id/44039103" "More broadly, the downgrade reflects our view that the effectiveness, stability, and predictability of American policymaking and political institutions have weakened at a time of ongoing fiscal and economic...

can a matter have negative energy? or more appropriately what makes some energy as negative?

Homework Statement Given a circular wire with radius R. Choose the origin in the center of the circle, the z-axis perpendicular to the circle. One halve of the circle contains a positive line charge \lambda, the other halve a negative line charge of the same magnitude. (a) Sketch the electric...

I'm designing a portable device running off of 2 AA batteries that requires positive both positive and negative 5v power at the same time. What is the best/cheapest way to achieve this?

If maths tells us 1 * -1 = -1 and it takes a positive cell to repel a positive cell ... could in theory a negative black hole never be reversed ?

For example: i) Someone lifts 2kg flowerpot 1m vertically upward. The work done by the gravity is -19.62 J? Then, if ii) A 3kg box on the floor is lifted vertically up onto the head and then lowered down to the shoulder. The shoulder is 150cm while the top of the head is 175cm measured...

Hi, Iam reading horowitz and hill and came through this paragraph in section 2.03 Emitter follower : Notice (Section 2.01, rule 4) that in an emitter follower the npn transistor can only "source" current. For instance, in the loaded circuit shown in Figure 2.8 the output can swing to...

Hi, Is a metric signature of (-,-,-,-) unphysical? Thanks,

Hi all, I've been using Faraday's law to find the EMF in a coil of wire in a changing magnetic field. EMF = -N (change in mag flux/change in time) for N loops I'm finding that the EMF is always positive regardless of whether the change in flux is positive or negative. I'm wondering at...

Protons have a magnetic moment of 2.8 μN, Neutrons have a magnetic moment of −1.9 μN. What is the meaning of the negative sign? Does the Neutron go a different direction in a magnetic field? How do they know it isn't just upside down? Is there any kind of a visual picture of a magnet that...

Why is the Time component in the Space Time Interval negative? The space time interval is defined to be: ds^2=dt^2-dx^2-dy^2-dz^2 or depending on the convention used it may also be: ds^2=-dt+dx^2+dy^2+dz^2 The equation is defining distance using the pythagorean theorem. This results...