Negative Definition and 1000 Threads

I can show that ##f(x) \ge 0## but I can not show ##f(x) \ne 0## ##x=y=t/2## then ##f(t) =f^2(t/2)\ge 0##

Griffiths Pg 133 4th Edition Why can't n be negative? Is there a reason for this? My thought is that if n is negative, as sine is odd, the negative gets absorbed into C, a constant. Is this correct? Would it be equally correct to let n be a negative integer? Thank you

I want to explain my thoughts longer, but since my English is terrible, I will try to keep it as short as possible. This is the Minkowski diagram for the question above. ct-axis is the worldline of the space station, and ct'-axis is the worldline of the spacecraft. What I am confused about is...

I use an online physics calculator a lot to help me for various reasons. When I input less than 1 second into a watt hour calculation it initially tells me it can not be a negative value although that does disappear and it does do the calculation. Example power 10 w time 0.01 seconds 0.1 J...

A diffuser normally decreases the velocity by increasing the area. With assumption of an incrompressible flow, according to Bernoulli, the static pressure increases. What happens if one "forces" the flow through a diffuser by applying a bigger pressure on the inlet than on the outlet?

the question is fairly easy to solve, integrating ##NiAB sin(\theta)## from ##\pi## to 0 or just do ##-NiAB(cos(0) - cos(\pi))## which gives you -2NiAB, but my textbook did not include the negative sign, is it mistaken?

What I mean is on a coordinate plane like below we take the positive x axis measure a certain distance x on it and take the infinitesmally small quantity dx next to it in the positive direction: Now can I do the opposite as in can I measure a distance negative x on the negative x axis and...

We'll be updating PF software this coming weekend. Hoping to fix some pesky bugs! Shouldn't be down for more than 15-20min. Likely Saturday morning.

My attempt: 4>19-3x Subtract 19 from both sides: -15 > -3x Divide both sides by -3: 5 > x Switch sides (change sign): x < 5 ! But Maths Genie tells me the answer is x>5 Where have I gone wrong?

Say I have 6 pencils. I want to times this by negative two. Now ignoring the rules that your teacher taught you work this out. 6 pencils negative 2 times. Negative one time would be 0 and another negative times would be -6 right? So 6 x - 2 = -6 according to simple logic. The calculator will say...

Suppose the following integration, ##\int_3^{-1} x^2 \, dx = \frac{1}{3}(-1)^3 - \frac{1}{3}(3)^3 = -\frac{28}{3}## However, if we have a look at the graph, The area between ##x = 3## and ##x = -1## is above the x-axis so should be positive. Dose anybody please know why the I am getting...

Based on the fact of observed cosmological redshift, scientists have proposed different ideas to explain. One interesting question is whether gravity does negative or positive work now: According to universe expanding in Big Bang theory (Lemaitre, 1927), obviously gravity does overall negative...

My father has an idea is powering vehicle using negative pressure. I'm trying to explain to him that I don't think that can work. He is saying that imagine you're in space and you try create negative pressure by keep on removing and the only thing that's preventing the collapse of the material...

Will the probability to provide a negative value of a Sz 1/2 spin system always be 0? If lambda 1 = hbar/2 and lambda 2 = -h bar/2 ?

So I have this question. I get all the working out, but then I feel like the answer should be; -2/(b-a). Then I thought -2/(-a+b) must just be the same thing... all good so far.. Then they somehow just to 2/(a-b) as the final answer.. I'm lost there. How does that conversion happen...

I have used root locus before but my confusion now is that the input is the negative feedback. Usually when I have negative feedback I consider the the error between the input (ideal) signal and the observed signal. Also, in this case what is the tranfer function since u = -k*y, and what does...

hello i would like to understand something, i found the right answer but there is still something i don't understand. here is the figure and here is my correct solution what i don't understand is why F(3,Q) is 3kQ/r^2 i mean why is the 3? i only calculat the force between q3 and Q so why...

A screenshot from a book which describes it: So I am trying to picture this one: 1. A laser is "pumped" through a cylinder made from lithium niobate which is placed at 90 degrees, perpendicularly...so that the laser passes through the body of the cylinder (and not through the 2 round ends)...

Im wondering if plasma is possible to be separated into a positive nucleus and negative electrons and contained within a magnetic bottle ? If possible, what is the most efficient method of achieving it ?

Conceptually, negative leap seconds are not much different than positive leap seconds. However, many or most IT systems probably have no provision for negative leap seconds and no testing for that event. Add to our list of time/date headaches; this one not Y2K related.

I do not mean neutral electrical charge, but a forth kind (if exists) I am in 9th grade, and someone asked the teacher if there is an electrical charge that is not positive, not negative and not neutral, maybe something in the middle of them. The teacher said that there is a charge like that...

Hi! So, I've actually already solved this problem.. for the most part. I have split up the work into two sections, floor 0 to 10, and floor 10 to 15. From floor 0 to 10, I did ## F_{elevator} = w_{pass.} + w_{elev.} ## ## F = (70)(20 (num. of pass.))(9.8) + (800)(9.8) ## ## F_{elev.} = 21560N...

At any point between A and C the point load is negative (downwards), in the shear force diagram: positive is upwards, so this slope is negative. The equation says the slope should be positive. Is this something to do with shear force sign convention?

Currently, dark energy is described as a being that exerts a negative pressure while having a positive energy density. {\rho _\Lambda } + 3{P_\Lambda } = {\rho _\Lambda } + 3( - {\rho _\Lambda }) = - 2{\rho _\Lambda } However, there seems to be a problem with the negative pressure assertion...

In MOSCAP, why does the band stop bending as soon as the Si Fermi level touches either the conduction band (inversion) or the valance band (accumulation)?

I was reading "Brief answers to big questions" By Hawking, the above pic is from a page of the book, it says that at the time of the big bang there was an equal amount of positive and negative energy, and that the negative energy never went anywhere, the space-time itself is a store of negative...

I am confused with the negative voltage supply connections in electric circuit. If i have circuit as below with -5V source it is same as below In the 2nd circuit the 5V is directly shorted with the ground, does it mean the circuit is not correct? Am i missing something? Please advise.

In this problem, it doesn't tell you where is the focal length. So how do you know if it is in front or behind the object?

I am confused with the solution. It says ##\vec E = \frac{\sigma}{\epsilon_0}##. Shouldn't E = ##2*\vec E = 2*\frac{\sigma}{\epsilon_0}##? Electric field of the positive plate and electric field of the negative plate.

Summary:: Figure b also shows that there is no negative sign in Faraday's Law. How do I know when to include the negative sign?

I have a cylinder that is separated with an insulator. In the internal cylinder there is a thermal source, while outside the insulator we have a thermal sink. The power of the internal cylinder is positive, while of the external one in total is negative. How I should interpet the results. Like...

I have in the past been criricised for inappropriate postings that I could have resolved with research so this time I have done the research first. The best solution I have found is from wiki "that causes it to experience a force when placed in an electromagnetic field." What causes the force...

I check the datasheet of LM 319 high speed comparator online. I was wondering if LM 319 can accept negative supply voltage(-10V) and its possible to produce a 10V to -10V square wave which oscillates along origin rather than just 10V to 0v as shown below.

Find a. Subtracting 4 is the same as adding $\boxed{(-4)}$ b. Subtracting -7 is the same as adding $\boxed{(7)}$ c. Subtracting a positive number is the same as adding a \boxed{negative} number, where that $\boxed{?}$ is opposite of the original number d. Subtracting a negative number is...

I know how it’s done. So let’s jump on the question. The displacement that came was negative 6 cm. I want to know how this formula describes perfectly negative displacements. I don’t understand the mechanism. If I assume ##ut## to be distance traveled in absence of g then what is ##-1/2gt^2##...

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Is zero reference level synonymous with the return path of a current, i.e., the negative wire? If so, where a ZRL is being used by a circuit, is the ground pin and the negative pin in a XLR port the same thing?

So I know that E = -ΔV/Δs. If I wanted to solve for change in potential I could rearrange this equation and get Δ = -E*ds. With that information I believe I can solve the problem below. But in both solutions provided below, the negative sign goes away. Now I know I can pull the E out because it...

In this case, there is negative feedback. ##V_{out}## is almost equal to ##V_{in}## in this case. But I really can't understand how to even proceed to find out the input impedance in this case, from the equation I know. Can someone help me out in figuring how should I proceed?

Trying to run the factoran function in MATLAB on a large matrix of daily stock returns. The function requires the data to have a positive definite covariance matrix, but this data has many very small negative eigenvalues (< 10^-17), which I understand to be a floating point issue as 'real'...

In orbital mechanics, the effective potential is given by ##\frac {1} {2} m r^2 w^2##, which can be expressed in terms of angular momentum ##L## which is conserved. Yet, https://web.njit.edu/~gary/321/Lecture17.html apparently shows the centrifugal potential as the negative of the above...

Does "absorbing" negative energy from gravity cancel the upward momentum of the pendulum? Or what? Where can I see energy being negative? Does it repel stuff? It sounds impossible.

I think I've got the numerator part figured out, but I'm really stuck on what to do with those negative phases in the last term and how to get this to all come together in the end. I feel like I must have made a mistake somewhere, but can't find it. Thanks in advance for the help!

DISTANCE METRIC, 2D: $$d = \sqrt{x^2 + y^2}$$ DISTANCE METRIC, 3D: $$d = \sqrt{x^2 + y^2 + z^2}$$ DISTANCE METRIC, 4D: $$d = \sqrt{x^2 + y^2 + z^2 - ct^2}$$ You SUBTRACT elapsed time from the spatial distance. Yes, elapsed time is called "imaginary distance," and vice versa. However...

It's probably the hyperbola, but I don't see how it's curvature is negative. It looks like 2 parabolas. thanx, paige turner

Hi, there. I am working with a model, in which the dimension of the Hilbert space is infinite. But Since only several states are directly coupled to the initial state and the coupling strength are weak, then I only consider a subspace spanned by these states. The calculation shows that the...

In a video, a person discussed how to solve modulus problems with a negative sign. This is the link of that video lecture. He showed two methods to solve the problem. The first method is commonly used. Later he showed another method where he used a number line and a graph. Unfortunately, I...

I am trying to understand why the conjugate of a signal in the time domain doesn't produce an exact flip of the frequency domain spectrum. There is always a one-pixel shift in the result. The MATLAB code is shown below. I use a flip for the conjugate spectrum to show that it doesn't match the...

I am a knitter and am interested using physics to explain the negative ease we see in knitting especially in rib [ (k1, p1) rib for example). I think some could be explained by the stretch-ability of the materials, e.g. wool, acrylic, but is there a movement of the yarn in between the "live"...

This is the circuit in question. During lecture, when checking whether this was negative feedback, my instructor said that if the v_out increases, then v- increases as well, which would lead to the next v_out decreasing because v_out = A(v+ - v-). I get how if v- increases the next v_out would...