What is Kinetic: Definition and 1000 Discussions

In physics, the kinetic energy of an object is the energy that it possesses due to its motion.
It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes. The same amount of work is done by the body when decelerating from its current speed to a state of rest.
In classical mechanics, the kinetic energy of a non-rotating object of mass m traveling at a speed v is










1
2


m

v

2









{\displaystyle {\begin{smallmatrix}{\frac {1}{2}}mv^{2}\end{smallmatrix}}}
. In relativistic mechanics, this is a good approximation only when v is much less than the speed of light.
The standard unit of kinetic energy is the joule, while the English unit of kinetic energy is the foot-pound.

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  1. AndreewL

    Angular Momentum, Inertia and Kinetic Energy?

    Homework Statement A large wooden turntable in the shape of a flat disk has a radius of 1.50 m and a total mass of 100 kg. The turntable is initially rotating about its vertical axis through its centre with an angular velocity of 2.50 rad/s. From a very small height a 100 kg sand bag is...
  2. F

    Understanding the Kinetic Trans Effect?

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  3. R

    What is the minimum kinetic energy for this roller coaster ride?

    Homework Statement A rollercoaster has a loop with a radius of 12m. The coaster travels 50m and at point A, enters the loop. The average frictional force on the coaster is 40N. The mass of passenger is 50kg. What is the minimum kinetic energy required at point A to generate a velocity of 27m/s...
  4. RoboNerd

    Question kinetic energy in circular motion

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  5. UMath1

    Kinetic Energy of two positive charges flying apart

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  6. RoboNerd

    Calculating Moment of Inertia for Rotating Objects: A Kinetic Energy Problem

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  7. ramialsaiad

    Derive the kinetic energy of a mass on two springs

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  8. L

    Assess the statements: about potential and kinetic energy

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  9. ccarit3007

    What is the total kinetic energy of the rod?

    Homework Statement Uniform rod rotates at axel. What is the total kinetic energy of the rod? Homework Equations deltaKrot = 1/2Iw^2 deltaKtrans = 1/2mv^2 The Attempt at a Solution I believe the rod has both rotational as well as translation energy because the rod is not rotating about its...
  10. N

    Do electrons have kinetic energy in an electrical circuit?

    I got a question towards kinetic energy and elektrical energy. They always talk about about particle accelerators or devices when talking about transformation of elektrical energy into kinetic energy of elektrons. But do elektrons also have kinetic energy when they are circulating in an...
  11. S

    Kinetic model of an ideal gas

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  12. S

    Question about static friction adjusting itself

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  13. D

    Find the minimum kinetic energy of two electrons in a 1D box

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  14. Kara386

    Kinetic energy of alpha particle in alpha decay

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  15. P

    Explain relationship of Kinetic energy and acceleration

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  16. R

    Solving for Kinetic & Potential Energy: Help Needed

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  17. B

    Kinetic Friction and Incline for a Car

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  18. S

    I Why does the kinetic operator depend on a second derivative?

    The formula T = -(ħ/2m)∇2 implies that T is proportional to the second spatial derivative of a wavefunction. What is the origin of this dependence? In classical mechanics, T = p2/2m. Is it also the case in classical mechanics that p2/2m is proportional to a second spatial derivative? I...
  19. D

    Is kinetic energy included in the equation E = hν for a photon?

    For a photon the energy is given by $$E = h\nu$$ Does this includes both kinetic energy and energy due to mass? If so then de Broglie gave the equation λ = h/p by equating hν with mc2 but since E = mc2 just gives the energy due to relativistic mass at that speed it would not include kinetic...
  20. P

    Momentum and percent kinetic energy loss

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  21. P

    Possible explanation for kinetic energy

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  22. Asleky

    Kinetic Energy v. Time Graph for Freefall

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  23. K

    Maximum Kinetic Energy of Photoelectrons from Irradiated Hydrogen Atoms

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  24. manaXmizery

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  25. S

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  26. S

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  27. normal_force

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  28. B

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  29. D

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  30. M

    I Ideal Gases: O2 & H2 - Kinetic Energy Comparison

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  31. P

    I Relativistic Kinetic Energy Derivation

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  32. R

    Question about coefficient of kinetic friction and distance

    1. Homework Statement m = 4.00 kg theta = 30 v = 1 m/s compression of the spring by the block , x = 0.3 m d = 5 m Homework Equations rule : Fk = μ k * N i must find Fk first to find μ k using conservation energy, [/B] The Attempt at a Solution First find N, N = m x g x cos theta N = 4 *...
  33. Dishsoap

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    Homework Statement I am looking at part C.[/B] https://scontent-ord1-1.xx.fbcdn.net/hphotos-xal1/v/t34.0-12/12782422_10205657311624690_1648245885_n.jpg?oh=79b686a8b74392888fab0b070b86627d&oe=56F7E1E4 The Attempt at a Solution Here I am looking at part C. My initial thought is that they have...
  34. O

    B Need help with algebra in proving kinetic energy is not conserved

    I'm trying to prove that kinetic energy is not conserved in inelastic collisions using the conservation of momentum. This is the set-up. An object A of momentum ##{m_1}{v_1}## collides inelastically with object B of momentum ##{m_2}{v_2}## using momentum conservation ##P_i = P_f## {m_1}{v_1} +...
  35. O

    Do all forms of energy fall under 'kinetic' and 'potential'?

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  36. L

    Question about momentum and kinetic energy

    First of all i am not a native speaker so i apologize for my english. Kinetic energy is velocity squared multiplied by mass, whereas momentum is just velocity multiplied by mass. I have read that the reason for this is because conservation of kinetic energy is related to symmetry of the motion...
  37. A

    I Kinetic energy with effective mass

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  38. T

    Kinetic energy of water vs ice

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  39. F

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  40. P

    Relativistics kinetic energy

    Homework Statement At what speed the kinetic energy of particle equal n times it's rest energy Homework Equations i use this equation ##T=(\gamma - 1)m_{0}c^{2} ## The Attempt at a Solution ##T=n(m_{0}c^{2})## ##n=\gamma -1## ##\gamma =n+1## ##\frac{1}{\sqrt{1-\frac{v^{2}}{c^{2}}}}=n+1##...
  41. Q

    Kinetic Energy After Some Time Has Elapsed

    A balla of mass 5 kg is dropped from a height of 10 meters. What is the kinetic energy after 1 second has elapsed?First i found the velocity using this equation V^2=2gh = 14m/s Then I used this equation to find Kinetic Energy KE=1/2mv^2 and got this 490 J. But i don't know how to find KE...
  42. Rocco the Stiff

    Kinetic bombardment effects

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  43. I

    I Probability density and kinetic

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  44. A

    Calculation of Kinetic Energy in Rotation Motion

    Homework Statement Respected Physics Gurus/experts...! I am confused in the application of Kinetic energy Expression, i.e, KE = (1/2)MVCM2+(1/2)ICMω2 I had been trying out this question actually(it's pretty simple though:-p)...--- "A rigid body is made of three identical thin rods each of...
  45. A

    Gaussian gun: Where does the extra kinetic energy come from?

    Probably a stupid question, but I do not get it... Here you can see an experiment demonstrating the Gaussian gun: Here I understand how momentum is conserved, i.e. the smaller mass of the ejected ball times its high speed is equal the bigger total mass of the recoiling masses times its...
  46. kini.Amith

    Classical A source for solved problems in Kinetic theory of gases

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  47. Fedor Indutny

    B Alternative Kinetic Energy Formulation and Goldstein's Problem 11

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  48. O

    Distinction between Kinetic Energy and Momentum

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  49. Gh. Soleimani

    My Case of Total Translational Kinetic Energy of Ideal Gas

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  50. B

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