A proton follows the path shown in (Figure 1) . Its initial speed is v0 = 1.4

Two 11cm -long thin glass rods uniformly charged to +13nC are placed side by side, 4.0 cm apart. What are the electric field strengths E1, E2, and E3 at distances 1.0 cm, 2.0 cm, and 3.0 cm to the right of the rod on the left, along the line connecting the midpoints of the two rods?

Specify the electric field strength E1.

Specify the electric field strength E2.

Specify the electric field strength E3.

Two 11cm -long thin glass rods uniformly charged to +13nC are placed side by side, 4.0 cm apart. What are the electric field strengths E1, E2, and E3 at distances 1.0 cm, 2.0 cm, and 3.0 cm to the right of the rod on the left, along the line connecting the midpoints of the two rods?

Specify the electric field strength E1.

Specify the electric field strength E2.

Specify the electric field strength E3.

Why is electromagnets so important in our everyday lives and how is it used.

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In a two-slit interference experiment, with a light source of unknown wavelength, the following data are measured:

slit separation, d = 0.22 mm,

distance of slits from the screen, L = 2.39 m, (large enough that the small-angle approximation applies),

separation between the m =

Senior physicists constantly complain they spend too much time on administration, teaching, getting grants, serving in committees, peer-reviewing articles, supervising, etc. . Do senior physicists conduct research by getting their post-docs and graduate students to do all the intensive work for them?

Context is 1D Ising model. Metropolis algorithm is used for simulate that model. Among all possible spins configurations (states) that algorithm generates only states with the desired Boltzmann probability.

Algorithm chooses spin at random and makes a trial flip. If trial satisfies certain conditions related to Boltzmann probability, flip is accepted. Otherwise flip is rejected and system is unchanged.

Define "acceptance ratio" as a percentage of accepted trials. Simulation shows that acceptance ratio is higher on higher temperature (behave as increasing function of temperature).

Questions:

Why Metropolis algorithm is not efficient at low temperatures?

Is efficiency of algorithm related to acceptance ratio?

Well, it does according to this preprint for certain scales.

What would be a simple way to explain MOND to a layman?

Does it ignore mainstream physics? How much?

It is well known in racing that driving the car on the ideal "slip angle" of the tire where it is crabbing slightly from the pointed direction produces more cornering speed than a lower slip angle or a higher one.

(More explanation as requested) I'm considering two main effects on the tire when in a turn:

The tread of the tire is twisted from the angle of the wheel it is mounted to. There is more force as speed increases, and generally, more twisting.

The tire slides somewhat at an angle on the road surface rather than rolling.

At low speeds, the angle between the pointed direction of the wheel (90 degrees to the axis of rotation) and the direction of travel is nearly 0. When the speed increases to the point the angle reaches about 10 degrees, the tire generate more grip and the car goes faster around the turn. (Higher angles produce lower grip)

So the grip is higher at 10 degrees of slip than at 0 or 20 degrees.

What is the physical effect that causes this increase in grip?

Fermilab seems to have ruled out monopoles with mass less than 850 GeV, but I have seen some estimates of the mass thought to be in the order of up to 1018 GeV, which, of course, would make them undetectable in any accelerators. By 2013, the LHC is scheduled to reach up to 14 TeV. The only disputed sighting of a cosmic ray produced magnetic monopole was in 1982 when Blas Cabrera reported discovering one (Valentine event monopole). This has never been duplicated. CERN has set up the Monopole and Exotics Detector MOEDAL. Other experiments set up to detect them are the Antarctic Impulsive Transient Antenna--ANITA, and the Antarctic Muon And Neutrino Detection Array, aka AMANDA. While both of these detected neutrinos, neither detected magnetic monopoles (looking for Cerenkov radiation produced by products of monopole interaction). Another method of detection is to look for induced current in a superconducting ring when a monopole passes through. Joseph Polchinski called the existence of monopoles

How does one build up an intuitive gut feeling for physics that some people naturally have? Physics seems to be a hodgepodge of random facts.

Is that a sign to quit physics and take up something easier?

Thanks for all the answers. On a related note, how many years does it take to master physics? 1-2 years for each level multiplied by many levels gives?

In a lot of laymen explanations of general relativity it is implied that the four dimensions of the space-time are equivalent, and we perceive time as different only because it is embedded in our human perception to do so.

My question is: is that really how general relativity treats the 4 dimensions?

If so - what are the implications (if any) this has on causality?

If no - can the theory support more than one time dimension?

"stability" is invoked as the justification for the axiomatic requirement that the spectrum of the generators of the translation group must be confined to the forward light-cone. The spectrum condition has pervasive, significant effects in axiomatic QFT. There seems to be no proof, however, that the spectrum condition actually ensures that a quantum field will be stable, partly because there is, AFAIK, no mathematical specification of what stability consists of in QFT. IF there were, I suppose the stability axiom would be central to axiomatic QFT instead of the positive spectrum condition.

Stability is intimately related with positive energy in classical physics, of course, but the concept of energy is rather different in classical relativistic field physics than in quantum mechanics, being the 00 component of the stress-energy tensor instead of being the 0 component of the 4-vector of generators of translations. The relationship between positive energy and stability in classical physics does not seem enough to justify an uncritical adoption of the spectrum condition in quantum theory as an axiom, which is supposed to be obvious enough that it is almost beyond question. Negative frequencies are certainly not ruled out for classical field theories, because the energy is not a linear functional of the frequency of the Fourier components of the field.

An axiomatic definition of stability would presumably have to specify what deformations would or should not affect the stability of a given construction. A building is only stable, for example, provided a strong enough earthquake does not occur, it is not stable sine die. Given that the deformations that are possible in quantum field theory are more varied than the deformations that are possible in classical field theory, the spectrum condition seems to require a more substantial justification.

Less axiomatically, Feynman integrals include negative frequency/energy components in intermediate calculations, though not in observables, which seems to bring the spectrum condition into at least some question.

Haag discusses the relationship of stability with the spectrum condition only extremely perfunctorily (p.29 of the 2nd edition of Local Quantum Physics), and I am not aware of an elaborate discussion by other authors. Is there one?

EDIT: Streater & Wightman, in PCT, Spin & Statistics, and all that, discuss collision states. Their discussion is entirely in terms of perturbation theory, which seems not adequate enough for an axiomatic discussion. However, because of asking this question I'm starting to see slightly more clearly why a conventional Physicist might be entirely satisfied with what there is on this.

EDIT(after acceptance of Tim van Beek's Answer): The other aspect of this is that the restriction to positive frequency is apparently not enough to ensure