Conservation Definition and 999 Threads

Conservation biology is the study of the conservation of nature and of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction and the erosion of biotic interactions. It is an interdisciplinary subject drawing on natural and social sciences, and the practice of natural resource management.The conservation ethic is based on the findings of conservation biology.

View More On Wikipedia.org
Recent contents Top users
  1. T

    Special relativity momentum and energy conservation

    Homework Statement Two identical particles of mass m travel towards each other at speed v; they combine and form a single new particle. By employing conservation of momentum and conservation of energy, what is the mass of this new particle in Homework Equations Relativistic momentum and total...
  2. C

    Masses Over a Uniform Cylindrical Pulley

    ηϖ1. Homework Statement Homework Equations I=½MR2 PE=mgh The Attempt at a Solution The first thing that jumped out at me was "uniform cylinder" so I went ahead and calculated the moment of inertia for the cylinder and got I=½(4.4)(.4)2 = .352 and held onto that. Then, I calculated the...
  3. A

    Height in conservation of energy problem

    Homework Statement A very Slippery ice cube slides in a vertical plane around the inside of a smooth, 20 cm diameter horizontal pipe. The ice cube's speed at the bottom of the circle is 3.0 m/s Vi = 3.0 m/s Height at top= 2(.20) = .40 Vf = ? Homework Equations KE(initial) + PE(initial) =...
  4. F

    Conservation of energy/Finding maximum height

    Homework Statement A 28-kg rock approaches the foot of a hill with a speed of 15 m/s. This hill slopes upward at a constant angle of 40.0∘ above the horizontal. The coefficients of static and kinetic friction between the hill and the rock are 0.75 and 0.20, respectively. a)Use energy...
  5. KetilT

    I What is the Simpler Name for Conserved Property of Spacetime?

    If we have come to realize that energy conservation is not the most general conservation law in our spacetime, isn't it odd that we don't have a simple name for the "real deal"? I bumped into this thought through Noether's theorem, which relates symmetries in fields to conservation of all kinds...
  6. donaldparida

    Conservative forces and conservation of mechanical energy

    Why do conservative forces conserve mechanical energy while non conservative forces do not? According to me, What makes the conservative forces path independent is that for a particular case they always act in a fixed direction irrespective of the direction of motion of the object on which they...
  7. M

    Conservation of Momentum Fluids Question

    Homework Statement I am studying for an upcoming exam and stumbled upon a website with a bunch of practice problems. I would typically state the question but this one is so long and requires a picture so here is the hyperlink to it: http://web.mit.edu/2.25/www/5_10/5_10.html Homework Equations...
  8. B

    Conservation of Angular Momentum

    Hi Folks, How would one use the conservation of angular momentum to explain the attached picture? The rod is held fixed horizontally..the person holds on to the cork and then let's go...apparently the glass is saved due to this conservation...
  9. Mr Davis 97

    Do We Include Signs in Conservation of Momentum Equations?

    When we use the conservation of momentum with, for example, collisions do we include the sign with the velocities or are the signs inherent in the quantity? For examples, would we write ##m_1v_1 = m_1v_1 + m_2v_2## or ##m_1v_1 = -m_1v_1 + m_2v_2## for a collision where a moving object hits a...
  10. Robzoid

    Conservation of Momentum with Friction?

    When reading lessons on the conservation of momentum, you usually see examples with colliding balls or something to that effect. These examples always seem to fail to mention friction. These balls will always come to a stop due to friction. How is momentum conserved when it is lost to friction...
  11. Vitani11

    Angular momentum conservation: determine velocity of impactor

    Homework Statement A uniform rod of length L and mass M hangs at rest from a frictionless pivot. The rod is hit a distance 0.8L below the pivot by a particle of mass m moving perpendicularly to the rod at speed v; the particle sticks to the rod. Following the collision, the maximum angle...
  12. jlmccart03

    Conservation of Energy Homework problem

    Homework Statement A ball of mass m falls from height hi to height hf near the surface of the Earth. When the ball passes hf, it has a speed of vf. Ignore air resistance. Consider the system T which consists of the ball only. Write an expression for each of the following quantities in terms of...
  13. E

    Conservation of Energy of Mass on Crane

    Homework Statement A mass is suspended from a crane by a cable of length L. The crane and the mass is moving at constant speed V. The crane stops and the mass on the cable swings out. What is the angle that the mass swings? If the angle is 50 degrees and L=6m, what is the initial speed of the...
  14. Summer95

    Figuring Out if A Force Field is Conservative or Not

    Homework Statement There is a collection of different force fields, for example: $$F_{x}=ln z$$ $$F_{y}=-ze^{-y}$$ $$F_{z}=e^{-y}+\frac{x}{z}$$ We are supposed to indicate whether they are conservative and find the potential energy function. Homework Equations See Above The Attempt at a...
  15. M

    Why conservation of angular momentum is not applicable here

    Comets travel around the sun in elliptical orbits with large eccentricities. If a comet has speed 2.0×104 m/s when at a distance of 2.6×1011 m from the center of the sun, what is its speed when at a distance of 5.2×1010 m . Express your answer using two significant figures I applied...
  16. F

    A How Do Conservation Laws Apply to a 4 Current in General Relativity?

    Consider a 4 current J^\mu and a metric g then conservation laws will require \del_\mu J^\mu = 0 my lecturer gave me a brief problem and I think I'm missing some understanding of it he writes What I'm not understanding is, where he states, if we choose B to be the time slice between etc...
  17. nysnacc

    Energy conservation with tension

    Homework Statement Homework Equations Conservative of energy mg(y2-y1) +1/2 k (s2-s02) = 1/2 mv12 +1/2 mv22 The Attempt at a Solution v1 = 0 at rest y2 = 0 bottom What I got is v2 = 8.20 m/s but not correct, I don't know how I can take into account the tension.. Fspring = -ks = -4000 N/m *...
  18. P

    I Force on a Spherically-Uniform Radiator Moving Through Space

    Let's say I have a spherically-uniform black-body radiator. It is losing energy, and therefore some of its mass, at a particular rate. From the frame of reference of the radiator, it has no momentum, but it has a changing amount of energy. From its frame of reference, the pressure on the...
  19. M

    Conservation laws in rotational movement

    Homework Statement Consider a uniform rod of mass 12kg and length 1.0m. At it's end the rod is attached to a fixed, friction free pivot. Initially the rod is balanced vertically above the pivot and begins to fall (from rest) as shown in the diagram. Determine, a) the angular acceleration of...
  20. S

    Angular Velocity in Linear Momentum Equation

    m1v1 = m2v2 v = rω m1(rω)1 = m2(rω)2 m1ω1 = m2ω2 Does this make sense?
  21. G

    Field-free formulation of ED: Conservation laws?

    Hi. In the (mainstream) books of electrodynamics I know, the electric and magnetic fields are introduced as force fields normalized to a charged test particle of 1 C. This makes those fields appear as an unnecessary, but convenient mathematical tool. They cannot be measured in the absence of...
  22. nysnacc

    Energy Conservation: K0 + V0 = K1 + V1

    Homework Statement Homework Equations U_initial = U_final The Attempt at a Solution K_0 = 10 m/s K_1 = 0 m/s (at peak) V_0 = mgh_0 V_1 = mgh_1 1/2 mv02 + mgh0 = 1/2 mv12 + mgh1
  23. J

    Decelerating charged particle and energy conservation

    Consider a charged particle moving with velocity v, having the energy 1/2 m v^2. Now we deccelerate the particle very quickly; so quickly that the radiated energy is greater than the kinetic energy (it can be arbitrarily large). Note also that energy obtained from decceleration is positive...
  24. S

    Average Angular Momentum Conservation? mω

    My textbook talks about the average angular speed that ω = angular displacement / time for the angular displacement to take place. So the question is like there is m1v1 = m2v2, can the velocity be instead average angular speed to have the conservation of momentum equation like this? m1ω1 = m2ω2
  25. S

    Conservation of Noether charge for complex scalar field

    Homework Statement Prove that the Noether charge ##Q=\frac{i}{2}\int\ d^{3}x\ (\phi^{*}\pi^{*}-\phi\pi)## for a complex scalar field (governed by the Klein-Gordon action) is a constant in time. Homework Equations ##\pi=\dot{\phi}^{*}## The Attempt at a Solution...
  26. G

    Looking for proof of Superpositional Energy Conservation

    Let's have waves with their carried power proportional to the square of their amplitude(s). The waves obey the principle of superposition. Before superposition, we can calculate the power output based on the amplitudes. After superposition, there will be new values for the amplitudes, but the...
  27. D

    I Confusion about derivation for isotropic fluids

    In Woodhouse's 'General Relativity' he finds an expression for the energy-momentum tensor of an isotropic fluid. If W^a is the rest-velocity of the fluid and \rho is the rest density then the tensor can be written as T^{ab} = \rho W^aW^b - p(g^{ab} -W^aW^b) for a scalar field p. The...
  28. A

    Antenna gain reciprocity violation of conservation of energy?

    I expect that others have already asked and answers this question but I could not find it with Google searches. My thought of this apparent antenna reciprocity violation is per below. Since antenna reciprocity states that an antenna will have same characteristics whether used a transmit...
  29. Q

    Conservation of Momentum Degrees of Freedom

    Hi I have been dealing with a fluid mechanics pressure gradient problem and from a statistical view point I can see how it resolves itself but am puzzled as to how it can occur at the molecular scale from a conservation of linear momentum perspective if Momentum is a conserved quantity While...
  30. M

    Conservation of Momentum Question

    Homework Statement An incompressible fluid of density ##\rho## flows steadily through a 2D infinite row of fixed shapes. The vertical distance between shapes is ##a##. Define station 1 as the space where velocity enters and station 2 where it exits. Also, velocity and pressure are constant...
  31. H

    Rotational Motion - Conservation angular momentum

    Homework Statement A 500.0-g bird is flying horizontally at 2.25 m>s, not paying much attention, when it suddenly flies into a stationary vertical bar, hitting it 25.0 cm below the top(Fig. P10.85). The bar is uniform, 0.750 m long, has a mass of 1.50 kg, and is hinged at its base. The...
  32. R

    Conservation of Momentum, Question Regarding Force

    So I read that the conservation of momentum is a result of: F1=-F2 <Newton's Third Law t1=t2 <Time in contact Therefore: F1*t1=-F2*t2 F=m(Δv/t) Ft=mΔv So we can conclude: m1Δv1=-m2Δv2 Therefore momentum is conserved. Now what force is this? Would it be the same normal force that exists when...
  33. E

    I A problem about momentum conservation.

    Imagine two equal charges, one at rest and the other moving uniformly. From Special Relativity we know that the electric field of the moving charge is different respect the one of the charge at rest. So the two forces of the interaction do not verify the law of action-reaction and there is a...
  34. D

    Simple Conservation of energy question

    Homework Statement Pole-vaulting is a fantastic example of energy being converted from one form to another. A pole- vaulter 1.7 m tall runs at 30 km/h (8.4 m/s) with her pole before starting her jump. The kinetic energy she generates is converted into elastic potential energy of the pole...
  35. R

    Conservation of angular momentum

    Hello everyone! I have a problem , to which I do not understand the law of conservation of angular momentum... I searched this problem on the web and it is obvious that I am making the mistake. So we have a rod of length ##L## and mass ##m## that is lying on a horizontal frictionless table. We...
  36. KT KIM

    Proof of angular momentum conservation

    This is from text [Introduction to Lagrangian and Hamiltonian Mechanics] on NTNU opencourse. Annnnd... I don't use english as my primary language, so sorry for poor sentences. I can't get two things in here. First, at (1.12) I can't understand how L dot derivated like that. Since I know...
  37. entropy1

    I T-symmetry and conservation of energy

    I read that since CPT-symmetry is not broken, and CP-symmetry is, T-symmetry must also be broken, is that correct? If that is correct, does that mean that energy isn't conserved?
  38. I

    B Conservation of energy in quantum physics

    I am still in secondary school so I probably shouldn't think about things this complicated (at least that's what it seems to me, complicated), but please correct me if I'm wrong. If I recall correctly, the position of an electron is never certain, and always based on probability, unless...
  39. UMath1

    Momentum conservation inelastic collection

    If a car crashes with a stationary tree and comes to stop, we could say that the kinetic energy of the car was converted to heat and that the collision was inelastic. However, conservation of momentum dictates that momentum is still conserved. How would that be possible given that neither the...
  40. Twigg

    Proof and Examples of Conservation of Etendue

    Hi all, Can you guys provide a proof of the conservation of etendue (simple/memorable is preferred, if possible!) and a few realistic, practical examples just so I can get the hang of the ideas and the calculations? Much appreciated.
  41. Quantum of Solace

    B Destructive interference and conservation of momentum

    If two photons traveling in the same direction but out of phase cancel each other out, what happens to the energy and momentum?
  42. E

    Angular Momentum Conservation -- Rope Problem

    Say there is a man swinging in space on a rope attached to a pivot. The man is rotating at some constant angular speed w. Now he climbs up the rope at some constant speed v. Apparently the angular momentum is conserved. As a result his speed increases. However, how does his speed increase if...
  43. F

    I Particle number conservation and motivations for QFT

    I've read that one of the primary motivations for the need for QFT is that quantum mechanics cannot account for particle creation/annihilation, however special relativity "predicts" that such phenomena are possible (clearly they have been observed experimentally, but I'm going for a heuristic...
  44. P

    I Deriving EM Energy Conservation from Lagrangian

    I'm trying to derive the conservaton of energy for electromagnetic fields with currents from the action principle, but I have some trouble understanding how the interaction term in the Lagrangian fits into this. The approach I have seen so far has been to express the Lagrangian density as...
  45. Xico Sim

    I Conservation of strangeness and eigenstates

    Hi, guys. In Povh's book, page 198, he says: "The strong force conserves the strangeness S and so the neutral kaons are in an eigenstate of the strong interaction." I do not see why this must be the case. My atempt to understand it: $$ŜĤ_s |K_0 \rangle = Ĥ_sŜ |K_0 \rangle$$ So $$Ŝ(Ĥ_s |K_0...
  46. H

    Momentum Conservation: Ball & Wall Impact

    What is the momentum of a ball at the exact point where it comes into contact with a wall?
  47. B

    Lagrangian Mechanics - Kepler problem, Conservation

    Homework Statement Attached. Homework Equations I am assuming the coordinate transformation is \vec{x}' = \vec{x} + \alpha\vec{\gamma} ? Then you have \vec{v}' = \vec{v} + \alpha\frac{d\vec{\gamma}}{dt} And r is the magnitude of the x vector. The Attempt at a Solution Part A. So to get the...
  48. N

    A formula for conservation of energy

    for my physics class a was working on a formula about conservation of energy could you guys tell me if it is somewhat right and stuff i forgot about =constant/s so this is my try making a formula about the total energy in the universe
  49. S

    Charge conservation on capacitor

    1. Homework Statement final charge on 3 microF be q1, on 2 microF be q2 and on 1.5 microF be q3 Intial charge on 3 microF is 360 microC and intial charge on 2 microC is 300 microF Homework Equations how the charge conservation takes place at the three junctions in the circuit The Attempt...
  50. MoZeeba

    Internal energy loss and momentum conservation question

    A uranium-238 atom can break up into a thorium-234 atom and a particle called an alpha particle, α-4. The numbers indicate the inertias of the atoms and the alpha particle in atomic mass units (1 amu = 1.66 × 10−27 kg). When an uranium atom initially at rest breaks up, the thorium atom is...
Back
Top