Conservation laws Definition and 114 Threads

Homework Statement A particle moves in a conservative field of force produced by a mass distribution. In each instance the force generated by a volume element of the distribution is derived from a potential that is proportional to the mass of the volume element and is a function only of the...

Homework Statement Given the energy-momentum tensor for a perfect fluid, what is the conservation laws that I can compute from \nabla_b T^{ab}=0 in a curve space-time. Homework Equations T^{ab}=(\rho + p) u^a u^b - p g^{ab} where p is the pressure and \rho is the...

Globalization makes that we can become aware of what other physicists, located at different remote places, have achieved. Kard1,2 is the author of the derivations of the fundamental equations of relativistic dynamics without using conservation laws. He starts by defining the momentum of a...

Homework Statement A claim has been made that an electron decays into 2 neutrinos traveling in different directions. Which conservation laws would be violated by this decay and which would be obeyed? Homework Equations Momentum: p = mv Mass-energy: E = mc² Electron Baryon number: 0...

Having a difficult time determining which laws and equations to use? A 15.0 kg block is attached to a very light horizontal spring of force constant 350 N/m and is resting on a smooth horizontal table. Suddenly it is struck by a 3.00 kg stone traveling horizontally at 8.00m/s to the right...

Here's the question: "An astronnaut working with many tools some distance away from a spacecraft is stranded when the "manueving unit" malfunctions. How can the astronaut return to the spacecraft by sacrificing some of the tools?" I don't quite understand what they're getting at here...

do you consider that conservation laws of momentum and energy are compulsory in the derivation of the fundamental equations of relativistic dynamics

I have read that in classical physics, symmetry under tranlsation implies conservation of linear momentum, and that symmetry under rotation implies conservation of angular momentum. Could you guys give me a brief explanation, or if the explanation is not brief Point me towards a good website...

Hi, I am working on a simulation and I have a problem of similar nature to the following: Consider a horizontal frictionless pipe containing two damped springs with the same diameter as the pipe. Suppose both of the springs are moving horizontally through the pipe, one faster than the...

The question I'm doing for homework that I can't get is... A spring is compressed 10.0 cm by an average force of 50.0 N. If the spring shoots a 20.0 g pebble straight up into the air, how high will it rise? It would be sooper awesome if you could help with this![COLOR=DarkSlateBlue]

This is probably a complete quack of an idea, but I can't get it out of my mind. I can't tell if it belongs more on an economics board, though. :bugeye: Could conservation laws exist for quantities which are not tangible? We all know there are laws like conservation of momentum...

Hi, I'm having a few problems with my Homework I'll post one question for now then if I find out where I got stuck I'll go on to my next question. Alright... "A 1500kg car accelerates up a hill in an attempt to pass a semi truck, it had an initial velocity of 12m/s if accelerated at a rate...

I have a question about the Dirac field. If as quantum field theory states , every point in the Universe is filled with "virtual" photons , and if these "virtual" photons in turn give rise to electron-positron pairs , which being components of matter and anti-matter collide and annihilate each...

Anyone know what quantity is conserved if the Hamiltonian (classical) is invariant under a Galilean boost? Also how would I prove that it is this quantity that is conserved? Cheers, Norm