Zero Definition and 1000 Threads

Homework Statement the vehicle needs to stop as close to a wall that is located anywhere from 9 to 12 m away. (The distance is not given exactly) The vehicle must be self propelled and has other specifications located here...

Absolute zero is the theoretical state in which a system reaches 0K, or NO energy present right? And if gravity affects everything with momentum and energy, would it cease to affect absolute zero systems because it includes no energy and thus no momentum? I posted a blog post on it here...

Hi all, I just did an exercice and there is one point that I don't understand (about Ampere's law). Homework Statement The exercice was about a cable with given diameter a, in which a small hole with diameter b is drilled in. The axis of the cable and the hole are parallel and the...

Apparently an ideal ammeter has zero resistance. But for a series circuit, why does it matter? The purpose of an ammeter is to give the reading for the amount of current going round a 'loop' of circuit. Having some resistance does not prevent the ammeter from giving a true reading, right? So...

Hello Forum, any number that a computer deals with is just an approximation...in what sense? Why is the number zero not possible? The number zero is often a very very very small number (10^-19) but never exactly zero. Why? thanks, fisico30

If two ends of a rope in equilibrium are pulled with forces equal in magnitude and opposite direction,why the total tension in the rod is not zero? Homework Equations The Attempt at a Solution

I have a question about the proof that I attached... 1) Since R/I is not the zero ring, we know that 1 \not= 0. What is the reason to say 1 + I \not= 0 + I instead of 1 \not= 0?2) Also, how do we compute something like (a+I)(b+I)? Isn't this correct (a+I)(b+I) = ab+aI+bI+I^2? 3) Finally, if we...

The following diff. equation describes the functionality of a system with respect to time. However, it is not known how the system will behave when stimulated. Apply a forward Laplace transform to determine damping ratio and pole zeros. Plot a pole zero diagram and comment on stability. d2y/dt2...

Suppose a beam of light is approaching you from a distant source. As it comes closer to you, it doesn’t hit you; instead it misses you by a 10 meter distance. How can the rate of acceleration of that beam relative to you, be explained(in non-jargon language)? What would the speed of that be...

http://www.tgdaily.com/general-sciences-features/68525-beyond-absolute-zero-temperatures-get-hotter#cRgTRdxE2qwYX5DR.16 It's been done in the lab, could this be seen in the cosmos? Could this affect entropies end game? What does this mean for the second law of thermodynamics?

Quantum Gas Below Absolute Zero! http://www.nature.com/news/quantum-gas-goes-below-absolute-zero-1.12146 I am a fresh undergraduate student and not expertise in fields. The link above shows an interesting research on negative temperature. I've visited wikipedia and found out that negative...

Absolute zero is often thought to be the coldest temperature possible. But now researchers show they can achieve even lower temperatures for a strange realm of "negative temperatures." http://www.livescience.com/25959-atoms-colder-than-absolute-zero.html

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

The vector field \vec{F} = <\frac{-y}{x^2 + y^2},\frac{x}{x^2 + y^2},0> has a zero curl, which means its circulation is zero. However \int \vec{F}.d\vec{s} around a unit circle on the xy plane is equal to (+/-)2\pi and not zero Is it because F is undefined at (0,0)? No, because Stoke's...

In rolling without slipping, why does the point of contact have zero velocity relative to the ground? If so, how can the point of contact move relatively to the ground? (It has to move relative to the ground, otherwise it cannot roll and must stay in its original position)

According to the Schwarzschild metric an interval of proper time d\tau at a fixed distance r from an object of mass M is related to an interval of co-ordinate time dt measured by a distant observer: d\tau = dt \sqrt{1 - \frac{2GM}{rc^2}} This is just the gravitational time dilation formula...

Is it possible for motion to exist at 0 Kelvin?

They say ZPE is the energy of the system at 0 K due to vibrations and even though the Schroedinger equation gives us the ground state minimum energy of the system (lets say by DFT/HF/QMC whatever), this energy is a little higher than that. My first question is, because I have learned that...

Is there a physical process in thermodynamics that results the value of the partition function as zero? When partition function is zero, then free energy becomes infinity, and it also yields negative entropy (at least within the system). Are there physical meanings of these?

Hello, I am currently reading about angular momentum. A sentence in my textbook sort of confused me: "when the translational velocity of the particle is along a line that passes through the axis, the particle has zero angular momentum with respect to the axis." I was wondering if someone...

I had a test recently and one of the problems was pretty basic. It gave you a table with the voltages at the gate, source, and drain of the device. Vt (Threshold voltage) was also provided, which was +1V. From there we were supposed to find Vgs, Vov(Overdrive voltage), Vds and the region of...

Homework Statement Here is the question along with the solution: I was wondering why the ICZV is at point A. Is it because the string is not slipping and thus the yo-yo is essentially "rolling" on the surface of the rope? Kind of like a bike wheel rolling on the ground?

Homework Statement I am seeing the steps on others who have worked this out and they are taking the pin as the pivot position. I thought a force's line of action that passes the pivot position produces zero torque? So i tried to make the center of mass the pivot position and each...

Homework Statement Let's say I've got simple y''(t) + 2y' + 1 = x(t), with maybe y(0) = 3 and y'(0)=1. the input x(t) is 12cos(20t). Using a laplace transform, determine zero state response of the output y(t). I know eventually I end up with the Y(s) and X(s) form, and then I have to...

It is known that Gauss's law for magnetism is ∇ ⋅ B = 0. If we write this in component form it becomes (∂Bx/∂x)i + (∂By/∂y)j + (∂Bz/∂z)k = 0, where i, j, k are unit vectors in a cartesian coordinate system and Bx, By, Bz are the components of the magnetic field on these axes. It would follow...

Homework Statement Suppose that S and T are sets with outer content 0, prove that SUT also has outer content zero. Homework Equations C(S) denotes the outer content. C(S) = C(T) = 0 Also : C(S) = inf \left\{{ \sum_{k=0}^{n} A_k}\right\} where Ak is the area of one of the...

why does this integral: double integral (x+y) dA , A is the area bounded by the triangle with vertices (0,0) (0,1) (1,0) equal 1/3 While this one, (x-y) dA , A is the area bounded by the same vertices equal 0? (not looking for the math, already worked them out, just looking for some...

Homework Statement The sum of the net torques is zero even f the numerical result is not. Rather than simply explaining that the net torque is close to zero, justify that your net torque is small, within the context of this experiment. 2. Attached is a pdf of the lab that we had this...

could we able to measure the velocity for a free particle with uncertainty equal to zero, could we able to have a certain values for its velocity, and let the uncertainty of the position to be infinity is there any theoretical restrictions on having a certain value for the velocity? is there...

zero gravitation! is it possible 1. Can you tell me the name of two particles having zero force of gravitation between them ?

Hi, I have an issue where I am squaring a very small complex number 1e-20 (FALFA2) which seems to make the value zero (both the real and imag part) and then dividing by it, the problem line is (all the numbers are complex): GALFA = ( FBETA * FAA / FALFA2 ) - ( FAB / FALFA )...

Hi I would like to know what is ∫1/x^2-∫1/x^2 from 0 to 2.is it zero or undefined meaning that it is infinity ? (because each integral is undefined at zero).

Homework Statement A point charge of -2 micro coulomb is located at the origin ,a second charge point of 6 micro coulomb is at x= 1m and y= 0.5 m Find the x and y coordinates of the position where the electric field is zero Homework Equations E=κq/ r^2 multiplied by unit vector...

Suppose a square matrix A is given. Is it true that the null space of A corresponds to eigenvectors of A being associated with its zero eigenvalue? I'm a bit confused with the terms 'algebraic and geometric multiplicity' of eigenvalues related to the previous statement? How does this affect the...

why rest mass of photon is zero? how to prove it by m=m'/√(1-v^2/c^2)?

The problem asks whether the set F of all functions from Z+ into {0,1} that are "eventually zero" is countable or uncountable. In my proof, I claimed countable. By definition, associated with each function f in F, there is a positive integer N such that f(n)=0 for n≥N. I took N' to be the...

Hi everyone For a pre-lab, I am asked to draw a square wave symmetric around zero volts. I am not sure what this graph looks like, can someone give me an example? Thank You

According to me Transfer function will be G(s)= (s2+2ζωn+ωn2)/((s+p1)(s+p2)) I assume from the given plot that ωn < p1 and ωn < p2 Then the bode plot will be as per me like following :From the Bode plot we can see for higher freq magnitude is amplified . So it will be High pass Filter. That's...

probability of AᴧBᴧBᴧC equal zero why!1 (B v AE)ᴧ( Ev C) So after multiplication you should have AᴧBᴧBᴧC But he didnt mention this, so it should by zero ,but why!11

Homework Statement Show that all Robertson - Walker models are conformally flat. Homework Equations Robertson Walker Metric: ds^{2}=a^{2}(t)\left(\frac{dr^{2}}{1-Kr^{2}}+r^{2}(d\theta^{2}+(sin\theta)^{2}d\phi^{2} )\right)-dt^{2} Ricci Tensor: R_{\alpha\beta}=2Kg_{\alpha\beta} Ricci...

A metallic sphere of radius R and specific resistance ρ is taken and two wires( negligible resistance) connected to it at random positions (say at an angle θ apart from each other.both the wires are perpendicular to the surface of the metallic sphere. Prove that the Magnetic field B at the...

Hi all, I got an idea why noise is having a gaussian pdf but didnot understood why it should be having zero mean. Why can't noise contain a dc content. -Devanand T

HeyI was wondering - is it physically impossible to make something absolute zero and then measure it to check if it was? I often read that we bring things down to "close to absolute zero" but it never is the full way. Is it because if human or electronic device, which ever it was that tried to...

Usually, in homework problems, I come across something like, "Let F be the set of all functions f:\mathbf{N}\rightarrow\{0,1\} that are eventually zero." But I don't really understand what is meant by that. Is it right to think about it as the set of binary numbers? If I take each f to be a...

The first thing that we should notice is that the leading coefficient $a_n = 1$. I was thinking about considering the factored form of p. I googled, and there is an algorithm called the "Schur-Cohn Algorithm" that is suppose to answer exactly this, but I can't find any information on it or...

I'm wondering if there are any theories of how time would be experienced by a fixed point in the universe. I realize the relative nature of the time dilation formula, but I find myself wondering if it would be any different if there was no movement at all. I mean, after all - we're all...

The integral form of gauss's law is used to determine the electric field of charge distributions which possesses a certain amount of symmetry. Now imagine using it in situations where the gaussian surface includes equal amounts of positive and negative charge. For example,imagine a point...

I read a post in an unrelated thread to the effect that some vectors do not have a direction. I assume the poster was referring to vectors with zero magnitude. At first this makes sense but the more I thought about it the more it seems to me that zero magnitude vectors do still have direction...

Homework Statement Why is the angular velocity of link BD the same as the angular velocity of ICD? Shouldn't it be ωICD=vD/rD/IC?

Homework Statement If we give X = R2 the non-standard operations (x, y,) ⊕ (x' , y') = (x + x' - 1, y + y' +2) (vector addition) and k~(x, y) = (kx - k + 1, ky + 2k -2) (multiplication by scalars) then X is a real vector space. - What is the zero vector of X? - If v = (x, y) is in X then...