Law is a system of rules created and enforced through social or governmental institutions to regulate behavior, with its precise definition a matter of longstanding debate. It has been variously described as a science and the art of justice. State-enforced laws can be made by a group legislature or by a single legislator, resulting in statutes; by the executive through decrees and regulations; or established by judges through precedent, usually in common law jurisdictions. Private individuals may create legally binding contracts, including arbitration agreements that adopt alternative ways of resolving disputes to standard court litigation. The creation of laws themselves may be influenced by a constitution, written or tacit, and the rights encoded therein. The law shapes politics, economics, history and society in various ways and serves as a mediator of relations between people.
Legal systems vary between countries, with their differences analysed in comparative law. In civil law jurisdictions, a legislature or other central body codifies and consolidates the law. In common law systems, judges make binding case law through precedent, although on occasion this may be overturned by a higher court or the legislature. Historically, religious law influenced secular matters, and is still used in some religious communities. Sharia law based on Islamic principles is used as the primary legal system in several countries, including Iran and Saudi Arabia.Law's scope can be divided into two domains. Public law concerns government and society, including constitutional law, administrative law, and criminal law. Private law deals with legal disputes between individuals and/or organisations in areas such as contracts, property, torts/delicts and commercial law. This distinction is stronger in civil law countries, particularly those with a separate system of administrative courts; by contrast, the public-private law divide is less pronounced in common law jurisdictions.Law provides a source of scholarly inquiry into legal history, philosophy, economic analysis and sociology. Law also raises important and complex issues concerning equality, fairness, and justice.
Hi,
In the Stefan-Boltzmann equation for radiation heat transfer, there exists expected parameters of any model (area, constants, etc.). However, the temperature is raised to the fourth power.
Can someone explain why?
I get that it could just be because it has been "experimentally observed."...
<< Mentor Note -- Two threads on the same question merged into one thread >>
How does the maximum Power equation change if there's an angle to the way the wind falls into the wind turbine's blades?
Example, when it falls vertically to the blades, it's
Pmax= 8/27Sρu13
But if there's for...
An open tank has the shape of a right circular cone. The tank is 8 feet across the top and 6 feet high. How much work is done in emptying the tank by pumping the water over the top edge? (The weight-density of water is 62.4 pounds per cubic foot.)
Given the figure, how can i arrive to this formula knowing that angular momentum is conserved?
I know that p = mv and L = p x r. So the initial momentum will be L1 = mV x R and the final momentum will be L2 = mv x r.
I am not sure how R will equal to b since the distance between the...
Homework Statement
A ski starts from rest and slides down a 22 o incline 75m long. Coefficient of friction is 0.090. What is the skiers speed at the base of the inlcline? Use energy methods
Homework Equations
PE=mgh
KE=mv2/2
W=Fd
The Attempt at a Solution
Since mass was not given I did PE=KE...
Homework Statement
I have posted the snapshot of the problem.
Homework Equations
Snell's law equations
The Attempt at a Solution
Now the problem says that laser travels through air vertically upward to reach the outer surface of the glass half-cylinder. If that is the case, then from Snell's...
Homework Statement
Okie so I'm working on my physics work, and I need to compare Charles' Law (for finding absolute zero) to another method used to calculate absolute zero.
3. Attempt at the Solution
For this, I was thinking of looking at Carnot engine, but I absolutely do not understand and...
Homework Statement
Homework Equations
∮E.dA = qencl/ϵ0
The Attempt at a Solution
(a) magnitude E
we use∮E.dA = qencl/ϵ0For a cylinder:∮E.dA = E(2πrL), thenqencl/ϵ0 = E(2πrL)E = qencl/(2πrLϵ0) E = λ/(2πrϵ0); WITH λ = qencl/L
(a) the magnitude E, qencl = Q1 + Q2 , thenE = (Q1 +...
Hi all,
I’m having some trouble finding a minus sign in a standard calculation I have been doing. I am trying to show that if there is no enclosed current around the example loop in the enclosed jpeg, the four piecewise paths add up to zero (for the line integral part of Amp’s law). For this...
Homework Statement
A metal ball of mass 1kg is heated by means of a 20W heater in a room at 20°C. The temperature of the ball becomes steady at 50°C. (a) Find the rate of loss of heat to the surrounding when the ball is at 50°C. fa) Assuming Newton's law of cooling, calculate the rate of loss...
Homework Statement
a car moving to the left with constent accelration. a ball is hanging from the ceiling held in 90 degrees to the ceiling until t=0, then it is realesed and start to swing.
find the max angle.
Homework Equations
Newton's second law
The Attempt at a Solution...
Homework Statement
Homework EquationsThe Attempt at a Solution
How do you know the left plate (or the right plane) produces a field (1/2ε) σ to the left and right? How do you apply Gauss Law? For one infinite plane, we can use Gauss law because of symmetry, so we can assume the electric flux...
I had a thought the other day and I am looking for someone to tell me why it does not work.
In consideration of energy be neither created nor destroyed, to me this would say there is not enough energy to continue expanding the universe.
I also make the conjecture the gravity never stop...
Ok, i am struggling to figure something out. I don't know why math is so much easier than physics haha.
ok, here is my struggle. I have two states, state 1 and 2, which i will call just 1 and 2.
1:
T=298kelvin
V=0.025m(cubed)
P=310Kpa
Mass1=Mass2
R=0.2870
2:
T=323kelvin
V=0.025m(cubed)
P=...
Homework Statement
Homework Equations
Ideal gas law
The Attempt at a Solution
The solution to this problem assumes the pressure inside the balloon is the same as the outside pressure, i.e. atmospheric pressure. Is this a valid assumption? I would guess otherwise.
Homework Statement
lim (1/x - 1/3) / (x-3)
x->3
Homework EquationsThe Attempt at a Solution
I tried to cancel the bottom (x-3) out by multiplying the top by 3/3 and x/x and then got ((3-x)/3x)/(x-3) but ended with 0/0 and the right answer is -1/9. The top part is confusing me.
So I was in the bus going to school. I sat in the back not directly underneath the emergency exit but more like behind it. Anyways, since it’s been raining consistently, the emergency exits sometimes leak. So I’m sitting down and my jacket sleeve gets wet with a drop from the emergency exit. I...
Hi.
Pascal's law states that static pressure in a confined incompressible fluid without gravity is the same everywhere. Is this law derivable from more fundamental laws? Some thoughts:
Is Pascal's law part of the definition of the liquid state?
If the liquid operates between two hydraulic...
Homework Statement
A 7.2-kg mass is hanging from the ceiling of an elevator by a spring of spring constant 150N/m whose unstretched length is 80 cm. What is the overall length of the spring when the elevator: (a) starts moving upward with acceleration 0.95m/s2 ; (b) moves upward at a steady...
Homework Statement
The magnitude of the electrostatic force between point charges ##q_1 = 26~\mu C## and ##q_2 = 47~\mu C## is initially ##F_1=5.70~N##. The separation distance between the charges, ##r_1## is then changed such that the magnitude of the force is, ##F_2=0.57~N##.
(a) What is the...
Homework Statement
What is a real-life example of the ideal gas law?
Homework Equations
PV = nRT
(Pressure x volume = number of moles x the gas constant x temperature in Kelvin)
The Attempt at a Solution
https://www.reference.com/science/ideal-gas-law-used-everyday-life-3dacbd6ebd3b5949...
A charge Q is placed at the centre of the square of side 2.90 cm, at the corners of which four identical charges q = 6.5 C are placed. Find the value of the charge Q so that the whole system is in equilibrium. Can someone help me figure out where I have went wrong, I began by finding the force...
In a problem in Landau’s mechanics (end of section 9) he asks for the quantity conserved in the field of “an infinite homogenous cylindrical helix.”
The solution is that the Lagrangian is unchanged by a rotation of dΦ together with a translation of hdφ/(2π) (about and along the symmetry axis)...
Hi all,
sorry for the condensed title of my post. Any other version of the question I'm trying to ask turned out to be longer than allowed.
So, my question is about the wording in some versions of Clausius' statement of the 2nd law of thermodynamics.
From time to time I read something like...
##dU = dw + dq ##
vs
##dU = dw + dq + µdN##
Which equation do we apply to a closed system involving chemical reaction? According to textbooks, the first equation holds for any closed system in the absence of fields and kinetic energy. However, later chapters use the second equation for...
I'm forking this off another thread where I brought it up but it was getting OT.
It is good enough for a first approximation but it is certainly not exact.
Consider a test mass one radius from a spherical body. Work out the contributions form two points diametrically opposed on the surface...
According to Hooke's Law, F=-kx where F is the restoring force, k is the spring constant and x is the length of extension/compression.
When an applied force compresses a spring, a restoring force will act in the opposite direction.
When a spring is compressed and is in equilibrium (not...
Homework Statement
An ideal gas has a molar mass of 40 g and a density of 1.2 kg m-3 at 80°C. What is its pressure at that temperature?
Homework Equations
PV=nRT
R constant= 8.314
n= number of moles
T= tempreture in kelvin
density=Mass/ Volume
The Attempt at a Solution
i simply solved it like...
Consider a conventional U-tube with both the vertical tubes having the same uniform cross section area A and the horizontal tube of length L, connecting those tubes containing an ideal liquid. Now the free surfaces in both the vertical tubes will be at the same height and will have pressure...
Homework Statement
I read in my textbook that the force exerted by a charged particle q1 on another charged particle q2 does not depend on the medium between them. Yet we multiply ε by ε(r) in coulomb's law when there is a medium present between the particles. Can someone please explain this...
Hello there,
I have been working on the efficiency of engine problems and have some trouble with this one. My question is very specific.
If you scroll down to the line encircled in red, you see that the Work they calculated there was 2662 Joules based on the formula derived for the work of an...
Hi there,
I was recently helping a friend of mine with a fairly standard electromagnetic induction problem (a basic sketch of the set-up is attached) where we have a current loop with resistance ##R## moving through a magnetic dipole and had to roughly sketch out the current induced in the loop...
Homework Statement
https://imgur.com/a/OLPyMfK
Homework Equations
F=ma
W=F*d
W=T2 - T1The Attempt at a Solution
For part A i figured it must be E because that is the only one that goes to 0 as the hit says.
but nothing about this problem makes any sense to me.
Where it says "You notice...
So, I was studying Maxwell's equations and I don't really understand the last one - Ampere's Law (with Maxwell's extra term added in). The bit I'm not able to understand is the term Maxwell added. How exactly does a changing electric field through a closed loop induce a magnetic field along that...
Imagine there is an radiation concentrator (winston cone) surrounded with extremely many layers of foil for radiation insulation, except at the smaller opening. Every part of the setup is initially in thermal equilibrium with the surroundings. The amount of thermal radiation flowing through the...
The following are 3 equations of Planck's law or Planck's distribution function. Are they all correct? How do they derive from each other?
Equation One:
From page 512 of http://metronu.ulb.ac.be/npauly/art_2014_2015/shockley_1961.pdf
We denote by Qs the number of quanta of frequency greater...
Hello All,
The purpose of my joining the Physics Forums is to request advise on the necessity of agile collaboration among technology, law and medicine to promote common good. I started out as an electronics/computer professional, work experiences certifying wired/wireless products and...
I am interested in evaluating light intensity variation in a digital image. A colleague wants to apply an inverse square law correction to account for distance variation. I am trying to justify that in this case, the inverse square law does not apply.
Treating each pixel as a detector, it has...
Homework Statement
What is the solubility of an unknown gas in water at 1.0 atm if its solubility at 3.0 atm is 1.02M?
Homework Equations
Henry's law Sg = k*Pg
The Attempt at a Solution
Sg = 1.02M/3.0atm * 1.0 atm = .34 atm
I'm not sure if Pg, the partial pressure of the gas, is 1.0 atm or...
This is not a homework. In Chapter 8: Central-Force Motion, in the Classical Dynamics of Particles and Systems book by Thornton and Marion, Fifth Edition, page 325, Problem 8-19, we are asked to calculate the mass of the planet Saturn. In the instructor's solution manual, the solution for this...
Dear Sirs,
If I take this explanation as being true "The heat is generated on the microscale when the conduction electrons transfer energy to the conductor's atoms by way of collisions."
So a "current" must have a quantum of kinetic energy going into the conductor (resistive element) and a...
My understanding of heat is the energy transferred as a result of temperature imbalance between systems.
If two systems at different temperatures are in contact with each other, a temperature change for both systems and an energy transfer Q is occurring.
It is known that Q=W for a closed...
Hi,
I'm sorry but I'm not sure if I should post it here or in homework section. It's not homework for sure.
This Wikipedia article, https://en.wikipedia.org/wiki/Kepler%27s_laws_of_planetary_motion, on Kepler's laws says the following under History section in the last para:
Newton was...
Newton's law's of motion have been used for hundred's of years, but the second law is wrong and here is why. Newton's second says that net force equals the mass of the object multiplied by the acceleration or F∑=MA. This is fairly simple and straight forward, but is easy to prove wrong. If we...
Homework Statement
I was wondering if and how we can apply Ampere's Law to a transformer?
I am just thinking about the bog standard transformer with a core, primary coil, and secondary coil.
1) How do I deal with the current from both coils?
2) Do I need to think about the opposing magnetic...
Homework Statement
One of the reasons a single photon could not produce an odd number of electrons and positrons is
a) energy would not be conserved
b) unattainable photon energies would be needed
c) matter would be created
d) charge would not be conserved
Homework EquationsThe Attempt at a...
Homework Statement
Homework Equations
Right Hand Rule
The Attempt at a Solution
I am not understanding why the force is left. I can only figure out that the current in the solenoid is moving clockwise because of the right hand rule. From there, I see that the induced current might be...
So I have been trying to derive peukerts exponent based on assumptions I know this won't be accurate but I am curious about the data. So I don't know the time to discharge the battery so I guessed 3 Hours the capacity at a 20 hour rate is 40Ah meaning the manufacturer rated discharge current was...