Law Definition and 999 Threads

Well, I guess that is pretty much my question.

If you take a bar magnet and place a wire with current a short distance from the end, Lorentz's law can be used to accurately predict the location and magnitude of the resulting forces. The same is true if you use a large volume uniform magnetic field to create an induced field in a bar ferrite...

I´m currently studying Newtons 2nd law and I don't get how can force only depend on mass and acceleration and not on velocity.. I mean, if I punch something with my fist going at constant velocity ( acceleration=0) it stills has a force right?

Hi , How to approach the problem? Thanks

I´ ve seen that Newtons law of gravity is considered and used very accurate to predict planet and satellites motion ( eclipses, etc..), but if space time is actually warped as Einstein told, how come Newtons law be accurate when it only depends on the mass and distance of to planets or stars...

My explanation: A circular coil is connected to an AC supply at a frequency of 30-50 kHz (radio frequency). Therefore, an alternate current will be running through this “primary” coil, producing an alternating magnetic field. This magnetic field periodically decreases in strength, alternating...

Hello guys, The third law says: "For every action, there is an equal and opposite reaction. The statement means that in every interaction, there is a pair of forces acting on the two interacting objects. The size of the forces on the first object equals the size of the force on the second...

Hi, I have measured a set of V-I values, and I have to provide the value of the resistance. I have used ac and dc current. The circuit was quite simple: power supply -> ammeter -> resistance -> [power supply] wave generator -> ammeter -> resistance -> [wave generator] Voltage was measured...

I want to know ohm's second law i search many times about it but every time the result is about ohm's first only, so can anyone help me??

I was wondering which equation do springs obey better: $$F=-kx$$ $$F=-k ln(x/x_0)$$ The first is Hooke's law, but the second comes when we consider the relative deformation instead of the absolute deformation. I am asking because I haven't seen any website stating the second equation, I just...

During an experiment, using Hooks law resulted in a spring constant of 7,8N/m while for the oscillation-method the constant was 8,6N/m. Could someone help me to clarify whay they differ and which vlsue is the correct one.

I have read in some books and articles of classic mechanics that the Newton's third law does not always hold, could you say an example to me?

Was Gauss' law originally derived from theory or discovered by experiment?

I'm reading the article https://www.researchgate.net/publication/267938119_ON_THE_GALILEAN_COVARIANCE_OF_CLASSICAL_MECHANICS (pdf link here), in which the authors want to establish the transformation rule for momentum, assuming only that ##\vec{F}=d\vec{p}/dt## and notwithstanding the relation...

I've come across this alternative formulation of Planck's Law which links the number density to energy gap n(E) = \frac{2\pi}{c^2 h^3} \frac{E^2}{exp\big(\frac{E-\mu}{k_BT})-1} I've tried visualising this relation and I imagine it will look similar to the spectral density relation but I'm just...

Gauss' law dictates that charge will only appear on the outer surface of a conductor. But if there's charge in a conducting cavity, the inner surface of the conductor will accumulate induced charge. So what's outer or inner should be redefined?

The significant digits of numbers in sets of numerical data supposedly follows "Benford's Law", which asserts that the probability that the first digit in a given data point is ##D## is about ##\log_{10}(1+ \frac{1}{D})##. An upshot is that we expect ~30% of significant digits to be ##1##. The...

(a) How far would a galaxy be whose speed with respect to the Earth is ##c##? Would it be observable from the Earth? r=rα=1.5⋅1026 m =1.6⋅1010 lightyears<4.65⋅1010 lightyearsr=rα=1.5⋅1026 m =1.6⋅1010 lightyears<4.65⋅1010 lightyearsr=rα=1.5⋅1026 m =1.6⋅1010 lightyears<4.65⋅1010 lightyears...

I'm reading a section in a textbook on the explanation of covariance of Newton's 2nd law under Galilean boosts. It's explained that ##\mathbf{a}=\mathbf{a'}## (where we're considering two frames ##S## and ##S'## moving inertially w.r.t. each other). Mass is assumed to not vary across the frames...

I've been stuck on this for sometime now, and am unsure how to approach this question.

Although I am not too sure how to answer this quesion I have tried below. I realize that an electromotive force is a supply voltage, the energy transferred per unit charge when one type of energy is converted into electrical energy. However, EMF is not actually a force. It is usually measured...

In derivations of capacitance it is standard to consider two oppositely charged, infinitely thin sheets. If we construct a Gaussian cylinder across one sheet, we obtain ##E_{1} = \frac{\sigma}{2\epsilon_{0}}## for one sheet, and then we can superpose this field with that from the other at an...

I do not know how to do this because in order to find the force of gravity it seemed to me i need to know the mass of the planet and vice versa, and for the 1st exercice i do not know whether the planet fills the astronaut's field of view. If it does in understand that i need to use trigonometry...

We have 4-tensor of second rank. For example energy-momentum tensor ##T_μν## , which is symmetric and traceless. Then ##T_{μν}=x_μx_ν+x_νx_μ## where ##x_μ## is 4-vector. Every 4- vector transform under Lorentz transform as (12,12). If we act on ## T_{μν}## , by representation( with...

This is my attempt, i am confused at some points a. r = 0; The Electric field is 0 b. At r = a/2.00; I verified the answer and it is non zero, but my understanding is that the net charge should be on the surface of the conductor. Hence the charge q1=5*10^-15 C, should go to the surface of the...

I actually found most of it out I'm just struggling with how to find the mass of the balls. I'm not sure how you would do that since could only derive two equations from the information given or are we assuming the mass is so small that it doesn't matter? Q = charge of one pith ball d =...

I was told to solve the second equation above for x to get l2 and l2, but that only gets me those in terms of other unknowns. I'm assuming I just need to solve t for my knowns, but I keep getting caught up by my unknowns. i.e., solving for x gives x = (l2*L*v2)/(l1*v1+l2*v2). Please note "l" is...

In a salt crystal, the distance between adjacent sodium and chloride ions is 2.82×10^−10m. What is the force of attraction between the two singly charged ions?

The force on a test charge Q due to source charge q, depends on both their velocities in addition to several other quantities. For electrostatics, the source charge is at rest (its velocity is zero) but the test charge may be moving. Then how does Coulomb's Law accommodate for this velocity of...

I really don't understand the theory of the above kind of questions. But from the little theory i understand the Electric field is 0 inside the conductor and all the charge goes to the surface and distributes equally. a. Since the E=0 inside the conductor the point charge distributes outside...

I have a question about the Second Law of Thermodynamics and the Stefan-Boltzmann law. These quotes are from http://www.ces.fau.edu/nasa/module-2/correlation-between-temperature-and-radiation.php “The Stefan-Boltzmann law, a fundamental law of physics, explains the relationship between an...

My attempt is ∅ = ∫E.dA. The direction of E is going out of the net towards +ve i axis. I am not clear on the direction of the Area, it can be either +ve i-axis or -ve i-axis. Which direction should i consider? ∅ = ∫3.dA = 3*∫dA ---->1 ∫dA is the area of the circle. A = π * (0.11)^2 = 0.038...

Struggling to see if I am doing this right or not from a section of a question I have been given I have drawn out a sketch of the circuit again, and labelled as to what my 1st and 2nd closed loop to be to then apply Kirchhoff's 2nd law I get a negative I_2 current which just indicates that...

Hi! This is a very simple question regarding terms of expressions. One law of motion is: F=ma Another, using L as the linear momentum, is: F = dL/dt If the first equation can be characterized (ignoring reference frames) as a "coordinate-based equation" (since is concerned with the second...

In my State, the statute says 2 of 3 brake lights required. How is one brake light any brighter than 3 or 4? Is my perception of reality flawed? & though I say it is just as bright, when asked to give a reason why, I can not produce any answer. Is it because it is simply “there” or is it...

I can't understand intuitively why the authors of the book expressed the cross product between the vectors dl and r (unit vector) as: dl sin(pi/2 - theta); isn't it supposed to be expressed as: dl sin(theta)?? So why did the authors put that pi/2 into the argument of sin function, that's my...

My attempt: I realized after i had tried to solve the problem that the current must be constant in the cables. But no information about where the cables has radius a and b is given so how would I go about to find an expression for the current? Thanks in advance!

In this case with a presence of the airgap, what should I do with the equation that is provided to be? Must the temperature gradient be caculated spearately (glass+air+glass) ? My tutor provided the hint that the heat flux should be constant for the windows, so in this case should I just omit...

I have a lot of questions as usually, but must begin with the difficult to understand moment which have started my explorations of the Kepler's second law. In the book of Steven Wainberg "To Explain The World", in the technical paragraph twenty one I have found the next formula which represents...

I'm posting the images of "Sommerfeld's Lectures on Theoretical Physics, Vol 2, Mechanics of Deformable Bodies" I apologize for posting the images rather than writing out the whole thing. But I did it to so that nothing should be missed, as writing out the...

A standard example consider a capacitor whose parallel plates have a circular shape, of radius R, so that the system has a cylindrical symmetry. The magnetic field at a given distance r from the common axis of the plates is calculated via Ampere's law: \oint_\gamma {\mathbf B} \cdot d{\mathbf...

Besides gravity that always works perpendicular to Earth and thus pulls apples from apple trees towards the ground, there must have been some sort of mid 17th century human made contraption, that used a constant force, produced to move objects with or without wheels, in a direction parallel to...

I have asked this question elsewhere. I have gotten no clear answer. What I already know: The interval (differential) sizes (areas) are different in terms of wavelength and wavenumber. The total energy is the same when the curves are integrated over all wavelengths or wavenumbers So please...

This is a very remedial question, so thanks in advance for you gentle indulgence :smile: Where do I find the quantization term (the "n") in Planck's Law?

If I want to find the tension in the rope that connects block A and B. I can apply Newtons first law. Sum of all forces in opposite direction equals 0. The forces that work on block A is Friction (Ra) and the force on the rope that pulls the block towards the right (T) So we get T-Ra = 0 and...

I have a simple sketch of the diagram, and I know I must use the vertical component of the magnetic field of the Earth when doing this problem I got an induced emf of 0.73 volts but I do not know if I correctly substituted the right values into faraday's law equation? Any help will be really...

Hi, I posted a similar question recently and gained some insight on these types of problems. However, I am slightly stumped on how to approach this variation of the problem. So I know that: - there is no net change in enthalpy of the blocks and the engine as the processes are reversible -...

So far all I can work out is that the angle of incidence of the outer two and inner two rays is zero degrees, however, I can't work out how to get started on the problem. I feel like I need to use vertical slowness rather than the normal snell's law since I'm working with a dZ rather than a dX...

So this is something I been thinking about. In venturi principle when a fluid or gas is moving across a tube when it is constricted the fluid has increased velocity. Because it in constriction the pressure goes down. But in Boyle law if volume is decreased the pressure goes up. So in the...