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. TheDemx27

    Conservation of Energy vs Conservation of Momentum problem

    Homework Statement We are trying to find out whether we can hit a weight ##m=3## kg up to a given ##h=15.24## meters with a hammer with a head of ##m=6## kg swung at ##v=10## m/s. Homework Equations KE=0.5mv^2 PE=mgh p=mv The Attempt at a Solution One solution is to even see if the energy...
  2. A

    Collision of two rolling bodies

    Homework Statement A solid sphere is rolling without slipping on rough ground with an angular velocity w and linear velocity v. It collides elastically with an another identical sphere at rest. Radius of each sphere is R and mass m. What is the linear velocity of the first sphere after it...
  3. vetgirl1990

    General question about conservation of momentum

    Referring to the Law of Conservation of Momentum: How is momentum always conserved? In a non-isolated system, an external force causes a change in momentum, so that initial momentum isn't the same as final momentum. Wouldn't this constitute a situation where momentum is not conserved? Or, is...
  4. jcruise322

    Conservation of angular momentum of disk and bullet system

    I know that the angular momentum is conserved in the below example, but intuitively I am struggling. Anyway, here goes! Homework Statement A bullet that is traveling without spinning hits and sticks into a filled disk tilted on its side an arbitrary distance "d" away from the center of mass...
  5. Mrchilko

    How Does Throwing a Partner Affect a Skater's Velocity in a Pairs Competition?

    Homework Statement In a pairs skating competition, the male skater is initially carrying his partner. Together they have a mass of 130.0 kg and they are are moving forward with a velocity of 2.5 m/s. If the male skater throws his partner forward at 1.5m/s, find the velocity of the male skater...
  6. dwdoyle8854

    Classical Dynamics -- Falling chain and energy conservation

    Homework Statement The statement of the question is:A chain of uniform linear mass density ##\rho##, length ##b## and mass ##M## hands as shown in the figure below. At time t=0, the ends A and B are adjacent, but end B is released. Find the tension in the chain at point A after end B has...
  7. N

    Momentum conservation in perfectly inelastic collision

    Dear Experts, Total momentum of a system is said to be conserved in perfectly inelastic collisions also. I have a slight problem trying to comprehend a simple example regarding the same. If a small mass 'm' , say a ball is thrown at a huge stationary mass 'M' , say a wall. If the collision is...
  8. Mrchilko

    How Do You Calculate the Mass of a Moving Ball After Collision?

    Homework Statement A ball rolls at a velocity of 3.5m/s toward a 5.0kg ball at rest. They collide and stick and move off at 2.5 m/s. What was the mass of the moving ball?[/B]Homework Equations Pa + Pb = 0 M(a)V(a) = - M(b)V(b)[/B]The Attempt at a Solution So.. The ball at rest had zero...
  9. E

    Easy conservation of energy problem? (long jump)

    Homework Statement m(person) = 60kg v1 = 3.0m/s v2 = 0 d = 2m y1 = -1m y2 = 0 A person is completing a long jump. At event 1 they are 1m in the air and are moving at a rate of 3.0m/s. At event 2 they are at rest on the ground, 2m from their initial landing place. What is the stopping force...
  10. WhiteG7

    Conservation of Angular momentum and linear momentum

    I've been a fan of this forum for a while, but never signed up for it, today I'm stuck on this problem and can't find anywhere other than Chegg but I don't have a premium account. 1. Homework Statement A meter stick is at rest on frictionless surface. A hockey puck is going towards the 30cm...
  11. C

    Basketball (Energy and its Conservation?)

    Homework Statement A basketball player shoots a 3-point shot. The 0.625 kg ball leaves the player's hands with a speed of 9m/s. It rises 2.4m before descending towards the basket. at the top of the ball's arc, what is its speed Homework Equations Im at a chapter named Energy and its...
  12. N

    Conservation laws with Killing fields

    Hi, In general relativity we have no general conservation of energy and momentum. But if there exists a Killing-field we can show that this leads to a symmetry in spacetime and so to a conserved quantity. Thats what the mathematic tells us. But I don't understand what's the meaning of an...
  13. A

    Conservation of Momentum - Finding Initial Velocity

    Homework Statement A 1500-kg sedan goes through a wide intersection traveling from north to south when it is hit by a 2200-kg SUV traveling from east to west. The two cars become embellished due to the impact and slide as one thereafter. On-the-scene measurements show that the coefficient of...
  14. physics411

    Conservation of Energy of cart Problem

    A 1.2 kg cart slides eastward down a frictionless ramp from a height of 1.8 m and then onto a horizontal surface where it has a head-on elastic collision with a stationary 2.0 kg cart cushioned by an ideal Hooke’s law spring. The maximum compression of the spring during the collision is 2.0 cm...
  15. CivilSigma

    Conservation of Work and Energy

    Homework Statement Hello, I am having trouble understanding the logic behind the solution to the posted problem. How did they deduce the equation for "Just after impact" ? I don't see how $$v_y = \sqrt{2g(0.6)}$$ What assumptions did they make or how did they get this simplified equation? I...
  16. A

    Can conservation of momentum be applied here?

    Take the case of Atwood machine, Where the masses of blocks are m and m,now,another ball of mass m strikes one of the blocks with a speed v and sticks to it. Considering our system as blocks+ball+string connecting the blocks(no pulley),can we apply conservation of momentum? Please explain...
  17. P

    Thermodynamics- conservation of heat and energy

    Homework Statement A 3.60 kg block of copper at a temperature of 92 °C is dropped into a bucket containing a mixture of ice and water whose total mass is 1.50 kg. When thermal equilibrium is reached the temperature of the water is 5 °C. How much ice was in the bucket before the copper block was...
  18. L

    How can I find the velocity of the combined cars after collision?

    Homework Statement A car of mass 1500kg is parked on a 30degree slope before rolling down a distance of 30m onto a flat section where it collides with a stationary car. The cars stick together and scrape along the road for 20m until they come to a rest. Calculate the velocity of the two...
  19. H

    Relation between energy conservation and numerical stability

    Hi, Consider the conservation laws for an isothermal linear incompressible flow governed by the mass and momentum equation. The kinetic energy equation is then solved to see if energy conserved. Can anyone tell me if once it is shown energy is conserved, it implies that convergence is obtained...
  20. S

    A Couple more "Rotation of Rigid Bodies" questions

    Homework Statement 1. It has been argued that power plants should make use of off-peak hours (such as late at night) to generate mechanical energy and store it until it is needed during peak load times, such as the middle of the day. One suggestion has been to store the energy in large...
  21. F

    Potential Energy and Conservation of Energy

    Homework Statement A 700g block is released from rest at height Ho(initial) above a vertical spring with spring constant k=400 N/m and negligible mass. The block sticks to the spring and momentarily stops after compressing the spring 19.0 cm. How much work is done A) by the block on the spring...
  22. Mr Davis 97

    Conservation of momentum of a skateboard

    Homework Statement A 48.0-kg boy, riding a 1.60-kg skateboard at a velocity of 5.80 m/s across a level sidewalk, jumps forward to leap over a wall. Just after leaving contact with the board, the boy's velocity relative to the sidewalk is 6.00 m/s, 7.40° above the horizontal. Ignore any friction...
  23. Yousufshad

    Introductory physics, energy conservation question

    Homework Statement A 226g block is pressed against a spring of force constant 1.25kN/m until the block compresses the spring 14.3cm. The spring rests at the bottom of a ramp inclined at 62.5° to the horizontal. Using energy considerations, determine how far up the incline the block moves before...
  24. D

    Conservation of Energy for the Universe

    The conservation of the energy of the universe requires that the universe is an isolated system. Is there any way that, in fact, the universe isn't a isolated system and we would be losing or gaining energy in the universe? Also, does this possibly mean that the universe won't necessarily end in...
  25. D

    Conservation of Momentum question

    Homework Statement Two carts sit on a horizontal, frictionless track; the spring between them is compressed. The small cart has mass m, and the mass of the larger cart is M = 4.65m. NOTE: Every velocity needs magnitude and direction (given by the sign). a) Suppose the carts are initially at...
  26. M

    Calculate recoil velocity using conservation of momentum

    Homework Statement A 70.0-kg man and a 55.0-kg woman holding a 2.50-kg purse on ice skates stand facing each other. (a) If the woman pushes the man backwards so that his final speed is 1.50 m/s, with what average force did she push him, assum ing they were in contact for 0.500 s? (b) What is...
  27. I

    Law of conservation of energy

    Does the law of conservation of energy make valid predictions when energy is converted from gravitational potential energy into kinetic energy?
  28. S

    Finding final velocity for Conservation of Energy Problem

    Homework Statement Problem statement and diagram in the photo Homework Equations K = 1/2 mv^2 U = mgh The Attempt at a Solution E_0 = E1 K_0 + U_0 = K_1 + U_1 using relevant equations and solving for v1 I get: v_1 = sqrt((v_0)^2 + 2gh_1) Then E_1 = E_2 solving for the final velocity and...
  29. SlowThinker

    Conservation of angular momentum and RoS

    [Moderator's note: thread spun off from a previous one on a related but different topic.] Well that's another question that has been puzzling me for quite some time and would love to know the answer to it... Imagine 4 tubes of equal length, making a square, with 4 identical photons running...
  30. G

    Conservation of 3-Momentum & Energy in RoS

    If the 3-momentum γmu and energy γmc2 are conserved in one frame, they will be conserved in any other frame. But I was thinking about RoS, since events may not happen simultaneously in another frame, will 3-momentum and energy always be conserved with respect to time?
  31. T

    Momentum Conservation: Large vs Small Car

    The question is: When a large car collides with a small car, which one undergoes the greater change in momentum: the large one or the small one? Or is it the same for both? I wanted to plug in dumb numbers: m_tv_{ti} + m_cv_{ci} = m_tv_{tf} + m_cv_{cf} lets assume the truck has a mass of...
  32. M

    Combine conservation of mechanical energy with the work-ener

    Homework Statement Find the horizontal distance the skier travels before coming to rest if the incline also has a coefficient of kinetic friction equal to 0.210. Assume that theta = 20.0°. Homework EquationsThe Attempt at a Solution
  33. naima

    Does the Klein Gordon Operator Preserve Compactness of Function Supports?

    Hi PF I have an operator in the set of indefinitely derivable functions on R^4. How can we caracterize the operators which send f with supp f compact to a function with compact support? My example uses the Klein Gordon operator K an its green's function adv and ret. let us take f such that...
  34. D

    Energy conservation and michelson interferometers

    What happens to the energy of a laser beam when it completely deconstructively interferes with itself in a michelson interferometer?
  35. D

    Conservation of energy violation of galvanic cell electron

    When a galvanic reaction reclaims its (single) electron, magnetic energy (about 0.356 eV) within a superconductor will remain, w/o a means of replacing the galvanic electron. During the reaction, electrical current from the single electron would correspond to the number of times per second...
  36. S

    Conservation of Energy Problem

    Homework Statement A man on his bike have an initial velocity of 8.5m/s. He begins to go up an incline that has a vertical height of 5.2m. Once he reaches the top of the incline, he only has a velocity of 3.00m/s. The man and his bike combined weigh 80kg. What is the total work done on the...
  37. mia_material_x1

    Conservation of Mechanical energy

    Homework Statement Attached figrue shows an 8.00 kg stone at rest on a spring.The spring is compressed 10.0 cm by the stone. (a) What is the spring constant? (b) The stone is pushed down an additional 30.0 cm and released.What is the elastic potential energy of the compressed spring just...
  38. Garlic

    Neutral particle oscillations / quantum number conservation

    Hello everyone, Why don't neutral particle oscillations have to obey conservation of (quark) flavor quantum numbers, with the example of neutral Kaon oscillations?
  39. Garlic

    Neutrino flavor conservation

    Hello everyone, Are neutrino flavors conserved in interactions other than neutral particle oscillations?
  40. bigsmile

    Why Does Dropping a Ball into a Well Result in Different Energy Sums?

    A 2.00-kg ball has zero kinetic and potential energy. John drops the ball into a 10.0-m-deep well. 1) Just before the ball hits the bottom, the sum of its kinetic and potential energy is: Zero J 2) After the ball comes to a stop in the mud, the sum of its potential and kinetic energy is: -196...
  41. H

    Comparing two energy systems - two boxes being pushed

    Homework Statement Starting from rest, two identical boxes are pushed through the same distance. Box A experiences a force F, while box B experience a force 2F. What is true about their final speeds?- The final speed of box A is twice that of box B. - The final speed of box A is equal to that...
  42. U

    Conservation of momentum or kinetic energy?

    Homework Statement A 100 kg person in space throws a 1kg sphere away from their body. The sphere starts from rest and ends up traveling 10 m/s away from the person. What is the kinetic energy of the person and the kinetic energy of the sphere? Is kinetic energy conserved?[/B]Homework Equations...
  43. asdfg

    Conservation of energy, bungee jumping

    Homework Statement A daring friend of yours talks you into bungee jumping from the Royal Gorge Bridge, in Colorado. Starting from the bridge (at rest), you launch off and fall first to the unstretched length of the bungee, 153 m. The bungee then stretches until you reach the full drop distance...
  44. halpmaine

    Conservation of Energy -- does it ever not apply?

    Are there situations when conservation of Energy does NOT apply? Thanks.
  45. D

    Conservation of Energy and Non-Conservative Forces

    Homework Statement Homework EquationsThe Attempt at a Solution 4a at x=-2 F=0N Potential energy=integration of F(-2)=Integration of 0=0 so it will reach minimum at x=-2? b. integration of F(-2)-integration of F(-2-h)=m(v-0)^2/2 am i right? 5 Centripetal force=mv^2/r=mgsinθ-Fn(normal force)...
  46. N

    Conservation of Energy and Momentum

    Homework Statement Homework EquationsThe Attempt at a Solution I know that the velocity of mass at the bottom of the swing is V = Sqrt(2gh), but I'm not sure how to get from there to the velocity of A. Is it as simple as Angular momentum of B = Linear Momentum of B?
  47. B

    Applying Conservation of Momentum along the Y axis

    Homework Statement A block of mass ##m## slides down a wedge of mass ##M## and inclination ##\theta## whose surfaces are all frictionless. Find the velocity of the block when it just reaches the bottom of the wedge. Homework EquationsThe Attempt at a Solution I was told that to solve this...
  48. zhengzhenglili

    An equation about local conservation in quantum mechanics

    Homework Statement Like ordinary wave, a particle’s wave function can be described as countless line of sine wave’s superposition. However it can also be clarified as vibration (the complex amplitude still follow the rule of local conservation) I think these two explanation are equal. Am I...
  49. S

    Matter/antimatter annihilation and conservation of mass

    I was hoping to learn a little bit more about matter-antimatter annihilation. As I understand it, when a particle meets an antiparticle, they are both annihilated and energy is produced. Does this contradict the laws of conservation of energy and conservation of matter? I haven't had much luck...
  50. P

    Rotational Motion: Energy and Momentum Conservation

    Homework Statement A child with mass m is standing at the edge of a merry go round having moment of inertia I, radius R and initial angular velocity x as shown. (The figure shows a disc moving anticlockwise, with the velocity v (Mentioned at the end) pointing upwards to the right most edge of...
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