What is Conservation: Definition and 999 Discussions

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.

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  1. George Keeling

    I Solving Geodesic Eq.: Mysterious Conservation Eq. (Sec. 5.4 Carroll)

    I'm still on section 5.4 of Carroll's book on Schwarzschild geodesics Carroll says "In addition, we always have another constant of the motion for geodesics: the geodesic equation (together with metric compatibility) implies that the quantity $$...
  2. r12214001

    Using Energy Conservation to solve this problem: Jumping on a spring scale

    I suppose spring compression to be X when jumpping from 1m. Therefore gravational potential mgh=760(1+X) and my cal:760(1+X)=0.5kX² why the solution manual state that 760=0.5kX²+760X
  3. B

    Cars Collide on a Hill, Conservation of Momentum

    QUESTION: ----------- For the purposes of this problem, we will define the direction of Vehicle A's initial velocity as the positive direction: While driving on a road that is inclined at an angle of 10 degrees above the horizontal, Vehicle A and Vehicle B are in a head-on collision lasting...
  4. kuruman

    Is Mechanical Energy Conservation Free of Ambiguity?

    Continue reading...
  5. ruivocanadense

    I Does Conservation of Momentum & Energy Hold in the C.O.M. Reference Frame?

    We know classical equations fail to follow conservation of momentum and energy when we are dealing with speeds closer to the speed of light. But does it fail in the center of mass reference frame of a system?
  6. J

    Influence of vacuum in the Conservation of energy

    I probably haven’t thought this through. A sideview of a closed container filled with air consisting of two vertical cylinders (with radius ##r_1## and ##r_2##) are connected by two horizontal tubes. The container is separated by a small and a large lid (red) that are circular and can move up...
  7. t2r

    Conservation of Energy: Why are Normal Forces Zero?

    Hello everyone, someone could explain me please, why the work of the normals forces are 0 ? He used with conservation energy equations. How should I refer to the displacement point ? Thx everyone !
  8. mgkii

    EM Wave - basic question on energy conservation in a wave

    I've searched threads and can't find easy explanation - sorry if I'm missing something basic / have a basic understanding error! In the classic picture of an EM wave with the Electric and Magnetic components oscillating at 90 degrees to each other, both components cross the middle axis at the...
  9. T

    Isospin Conservation: Calculating I3 and I

    I got the I3 values for the tau(minus) to be -1, as charge is -1 and Y=0. For muon(minus) i got I3 to be -1 too using the same equation and the anti electron neutrino to have an isospin of zero (since Q=0, Y=0). This shows I3 to be conserved (which is needed for strong interaction i believe)...
  10. J

    B Redshift & Energy Conservation: Questions Answered

    Hi, I have read over several threads already on this and have a few questions if someone could please answer that would be great: 1) The threads seem to suggest that energy is not conserved (or at least it isn't a requirement) on the scale of the universe. Why does it not have to be conserved...
  11. A

    Energy conservation for objects hanging from a pulley

    I have some conceptual questions about this task. In order to get the correct result (I checked the textbook answer) in part (a) I had to assume that the speed for each block is the same at all instants. And that if one block moves down x meters, the other one will move up that same amount of...
  12. Like Tony Stark

    Angular Momentum Conservation in Spacecraft Orbits

    Tell me if I'm right: A) Angular momentum is conserved because there are no external torques. Linear momentum isn't conserved because gravity is acting on the spacecraft . Mechanical energy isn't conserved because it has to change between different orbits. B) Parabolic orbit...
  13. G

    I Do collapse interpretations respect conservation laws?

    Hi. As far as I know, during the unitary evolution of quantum states, conservation laws are respected. Obviously this can't be true for the measurement process, if we only look at the system and exclude the observer. Now the simple explanation I've heard about this is that in quantum mechanics...
  14. C

    Momentum conservation for a free-falling body in GR

    Hello everyone! It seems I can't solve this exercise and I don't know where I fail. By inserting the metric on the lefthand side of I. and employing the chain rule, the equation eventually reads (confirmed by my notes from the tutorial): $$m\frac{\mathrm{d}p_\delta}{\mathrm{d}t} =...
  15. A

    Conservation of energy given the Earth's rotation?

    So Earth and everything is spinning around at 1000mph at the equator. From our perspective we are at a standstill. But let's say a fighter jets flies east to West against Earth at same speed, so now relative to someone in space, the Earth spins but the plane is at a standstill. Wouldn't that...
  16. V

    Moment of inertia, conservation of angular momentum and energy

    When I solved the problem using the conservation of angular momentum, I have got the correct result (ω = 0.006 rad/s). However, when I tried to find the answer using the conservation of energy the result was incorrect and I do not understand why.
  17. JD_PM

    Laser beams interacting with a screen | AM and momentum conservation

    a) On the black part, all incoming light is absorbed. This means that the momentum of the left-light beam doesn't change (i.e. momentum before hitting the black screen is ##\vec p_0## and after hitting it is zero. Thus ##\Delta \vec p = \vec p_0##). If momentum doesn't change, we get no...
  18. Luke Tan

    Conservation of Energy of the Center of Mass

    In classical mechanics, the energy of a system of particles (say with 2 particles) in an external field is given by $$E=\frac{1}{2}m_1|\vec{v}_1|^2+\frac{1}{2}m_2|\vec{v}_2|^2+V(\vec{r}_1)+V(\vec{r}_2)+V'(|\vec{r}_2-\vec{r}_1|)$$ Where V is the potential energy of the external field, and V' is...
  19. Physicsboi123

    Energy Conservation of a Vertical Spring

    Using conservation of energy, 0.5kx^2=mgh=mgx 0.5kx=mg 0.5kx=mg, x=0.15, m=9, g= 9.8 So isn't it k= 1176N/m? For this problem, I understand that you can't use conservation of energy, but why? There is gravitational potential energy at the top and spring elastic energy at the bottom, and no...
  20. Saptarshi Sarkar

    Is 2D Conservation of Momentum Possible? A Visual Analysis

    I am unable to find any angle for which the horizontal and vertical components of the linear momentum are conserved. I have added an image of my attempt
  21. CaglarKorkmazgoz

    Spring and Energy Conservation

    Hello, I am new on this forum, so if I make any mistakes please inform me. Thank you. I wonder why I cannot use forces instead of energy conservation in this question. The question is: "How far (x = L) does the spring stretch before the masses stop moving? Express your answer in terms of m, k...
  22. Amik

    Conservation of momentum — Water dropped from a firefighting airplane

    I could not unserstand part d.Does problem ask about plane's speed immediately after it starts to drop water or after the water is dropped completely?
  23. Amik

    Conservation of momentum when a ball hits a wall

    I think we can.Although the wall is not moving, it is just because the wall has a huge mass.As rhe law of the conservation of momentum states(suppose the ball hits the wall from the left), when the momentum decrease by J, the momentum of the wall increase by J, which means the momentum of the...
  24. Saptarshi Sarkar

    Total probability conservation

    I found out that the operator H is not a Hermitian operator but I didn't understand the second part of the question. What do I calculate the probability of?
  25. E

    Conservation of Momentum involving Vf, elastic collisions

    I tried solving it using this method and I got 12.5m/s, and assumed the collision was elastic. The answer is actually 6.32m/s [41.5 degrees counterclockwise from the original direction of the first ball]; the collision is not elastic: Ek = 12.1J Ek`= 10.2J I have absolutely no idea how the...
  26. AL115

    Conservation of momentum in a bullet-block-spring system

    According to the first equation, the final potential energy is equal to the initial kinetic energy of the block. So that means that Vblok is the instantaneous speed of the block right before it moves to the right and compress the spring, right? But doesn't the second equation (The initial total...
  27. S

    Conservation of Momentum: Elastic Collision of Two Masses

    I really want to know which answer is correct. I don’t really know if I should include velocities to the left as negative velocities in the equation. Is it -1 or 4.33? Please help! Thanks!
  28. U

    Solving a Spring-Mass-Box System:Energy Conservation

    Upon reading, realized that equations of consevation of energy would be of use for this question. I considered the energy of the system - the spring mass and box - taking into account that there will be Elastic potential energy of the spring, and we can arbitrarily set the intial positon(A) of...
  29. nuclearfireball_42

    Is Bernoulli's Equation related to the Conservation of Mechanical Energy?

    So the Bernoulli's Equation.. My question : Are the terms on the left hand side equal to the total mechanical energy? So can I rewrite this equation as ?
  30. U

    Energy Conservation as an explanation for v=0 for spring mass system

    My Solution: For the displacement graph, the gradient is crucial to predict the behaviour of the displacement of the block through time. At 1: System is released - velocity is zero, considering forces acting on block, kx < mg, as block is observed to move downwards, and object is...
  31. L

    How Does Faraday's Law Impact Momentum Conservation in a Magnetic System?

    Hello to all. Second post here so I apologise if I post to the wrong place with wrong altitude etc We have a schematic of a problem like here: https://www.physicsforums.com/threads/conducting-rod-is-free-to-move-over-a-loop-under-influence-of-b-field.750763/ The conducting rod ab shown in the...
  32. PHYSICSSSTUDENT

    Conservation of energy in a bullet-wooden block impact system

    Suppose a bullet with high speed strike a wooden block and move together after collision. We know there is loss in total KE of bullet-wooden block system. The question is, if the part of the loss in KE of the bullet is transfer to heat energy, HOW to prove the CONSERVATION of ENERGY in this...
  33. benny1993

    Conservation of Angular Momentum

    Suppose I have a system of two disks (identical in mass and size) one is fixed to a shaft at it's center point and rotating due to an external torque that's removed as soon as the rotational motion begins. The second disk is dropped from rest over the rotating disk and sticks together to the...
  34. T

    Conservation of Energy of a Spring with Weight Added

    I'm all messed up on this problem. I see you can get the solution (74cm, as listed in the back of the book) by simply setting mgh=1/2kx^2, saying that h=x, and then adding 15 cm to that since that's the original length of the spring. This is the solved solution I was given. But now I think...
  35. jisbon

    Conservation of angular momentum?

    Not sure what to do here, except using the conversation of angular momentum. Even then, is angular momentum conserved in this case even after attaching an external object here? Else, what laws can I use to solve this problem? Using conversation of angular momentum: $$\dfrac...
  36. K

    I Conservation of Energy Momentum Tensor

    Unfortunetly, I found across the web only the case where there's no source, in which case ##\partial_\alpha T^{\alpha \beta} = 0##. I'm considering Minkowski space with Minkowski coordinates here. When there's source, is it true that ##\partial_\alpha (T^{\alpha \beta}) = 0## or is it ##\int...
  37. Sabra_a

    Momentum conservation equations

    I attached a PDF file where it clearly show the question and I showed my solution because trying to type it here will be quite hard I want to check if my solution is correct
  38. Alexandra Fabiello

    Using the Conservation of Energy to find the Radius of a Bowl

    v1 = 0 m/s v2 = 2.5 m/s y1 - y2 = distance a quarter of the way around the bowl (since we're neglecting friction) mass can be factored out, so it isn't needed, and some simplifying and the like gets this formula: v22 = v12 + 2g(y1 - y2) so 2.52 = 0 + 2(9.8)(y) 6.25 = 19.6y y = 0.318877551 m *...
  39. S

    Arrow strike, Avg force, Conservation of energy

    The arrow is following projectile motion to the target when released from an archer's bow. v vertical = 10ms^-1 v horizontal = 50 ms^-1 resultant v = √2600 mass of arrow = 20*10^-3 I attempted to use F avg = mΔv/Δt to calcualte the average force where Δt = 5*10^-3 /...
  40. S

    Conservation of energy when placing two inductors next to each other

    This is more like a theoretical question of my own than actual homework. Say there is a circuit with a current source and an inductor. There is a current ##i(t)=at## going through the inductor. We now place a new circuit with an inductor and a resistor next to it. The current ##i(t)## causes a...
  41. RUTA

    Insights Exploring Bell States and Conservation of Spin Angular Momentum

    Continue reading...
  42. MathematicalPhysicist

    I Derivation of the conservation of total energy and momentum

    I want to derive from ##T^{\mu \nu}_{,\nu}=0## the equation: ##\int T_{0\mu}d^3 y=constant##, I don't see how exactly. From the derivative I know that ##T^{0\mu}_{,\mu}=0##, but I don't see how to integrate this equation, it's ##T^{00}_0+T^{0i}_i=0##. But how to proceed from here? Thanks in...
  43. S

    Conservation of energy: a mass and pulley system

    The solution is an application of the law of conservation of energy. Start with equation (1). The masses are in equilibrium and are not accelerating. This implies that ΔK = 0, because the kinetic energy will not change without acceleration. Thus, we are left to find equation (2) in terms of θ...
  44. N

    A Conservation of Quantum Information

    I can't seem to wrap my head around the notion of conservation of quantum information. One thing that might help that is if someone can tell me what the associated symmetry is. For example, phase symmetry leads to conservation of electric charge according to Noether's theorem; a fact that...
  45. entropy1

    I Conservation of energy and measurement problem

    If we have a two dimensional measurementbasis, then we have two possible outcomes of the measurement. Now I figured: considering the law of conservation of energy, if one particle goes in, one and only one can come out. So outcome "both results simultaneously" cannot happen, for that would...
  46. jisbon

    Conservation of Angular Momentum

    Hi, Since this is a question about COAM (Conservation of Angular Momentum), I will assume I can leave out the part on translation and just use the formula below: ##Initial Angular Momentum= Final Angular Momentum## whereby ##I = \frac {1}{12}ML^2## (of rod) So, ##\frac {1}{12}ML^2(1.5)=\frac...
  47. B

    Conservation of Momentum vs Constant k for an Ideal Spring

    I encountered a weird conflict between my thought process and that of author's solution in book: The common viewpoint of both of us were invoking conservation of energy of this SHM system But the author proceeds to solve it using conservation of momentum, taking the new mass added to system as...
  48. TheQuestionGuy14

    B Does a field's vacuum density violate conservation of energy?

    The vacuum density, or the zero point energy, of a field, doesn't change as space expands, it remains constant. But, aren't particles and virtual particles just fluctuations of these fields? Meaning as space expands, more and more particles are being created, violating conservation of energy?
  49. KingOfDirewolves

    Classical Mechanics Problem Based On Conservation Of Energy

    I have tried using Conservation of Energy but I'm getting incorrect answer.
  50. yash_it_is

    Gauge pressure in Momentum conservation of fluids.

    I want to ask why is it that we use gauge pressure instead of absolute pressure in CV analysis for momentum conservation of fluids. I did read that because P(atm) would be present everywhere so it won't have a net effect on the CV but it's highly non intuitive as I can't apply force balance on...
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