What is Energy: Definition and 999 Discussions

In physics, energy is the quantitative property that must be transferred to a body or physical system to perform work on the body, or to heat it. Energy is a conserved quantity; the law of conservation of energy states that energy can be converted in form, but not created or destroyed. The unit of measurement in the International System of Units (SI) of energy is the joule, which is the energy transferred to an object by the work of moving it a distance of one metre against a force of one newton.
Common forms of energy include the kinetic energy of a moving object, the potential energy stored by an object's position in a force field (gravitational, electric or magnetic), the elastic energy stored by stretching solid objects, the chemical energy released when a fuel burns, the radiant energy carried by light, and the thermal energy due to an object's temperature.
Mass and energy are closely related. Due to mass–energy equivalence, any object that has mass when stationary (called rest mass) also has an equivalent amount of energy whose form is called rest energy, and any additional energy (of any form) acquired by the object above that rest energy will increase the object's total mass just as it increases its total energy. For example, after heating an object, its increase in energy could be measured as a small increase in mass, with a sensitive enough scale.
Living organisms require energy to stay alive, such as the energy humans get from food. Human civilization requires energy to function, which it gets from energy resources such as fossil fuels, nuclear fuel, or renewable energy. The processes of Earth's climate and ecosystem are driven by the radiant energy Earth receives from the Sun and the geothermal energy contained within the earth.

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  1. D

    Can High Velocity Cause Hailstones to Melt?

    I'm pretty sure the hailstones are likely to melt/disperse because 824 m/s is a high velocity but can someone help me elaborate why it would melt?
  2. W

    Determine how much energy the alpha particle carries

    I can follow through all of this worked example until the final step 55/56x4.84= 4.75MeV Where does the 56 come from?
  3. R

    I Why is momentum considered a vector and kinetic energy a scalar?

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  4. MrS

    I Open channel flow: derive function for energy slope on friction?

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  5. G

    B Could the Pistol Shrimp's Energy Event Hold the Key to Cold Fusion?

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  6. M

    Theoretical question about a new Energy and implications of using it

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  7. rudransh verma

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  8. B

    A How to slow down a high energy neutral molecular beam

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  9. P

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  10. guyvsdcsniper

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  11. B

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  12. Danny_aero

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  13. L

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  14. Dario56

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  15. Dario56

    I Kinetic Energy and Potential Energy of Electrons

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  16. A

    Finding kinetic energy and initial velocity of a cart over time

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  17. rudransh verma

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  18. W

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  19. Amaterasu21

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  20. TechmoUnity

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  21. rudransh verma

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  22. penguin46

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  23. Zeal Faust

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  24. Anmoldeep

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  25. S

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  27. T

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  28. guyvsdcsniper

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  29. K

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  30. Istiak

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  31. R3ap3r42

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  32. L

    Work and kinetic energy comprehension question

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  33. P

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  34. L

    I The time derivative of kinetic energy

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  35. L

    Doubts on Exercise Wording: Energy Density & Poynting Vector

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  36. RogerWaters

    B How do the candidates for Dark Energy 'work'?

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  37. RogerWaters

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  38. jeffinbath

    B Can the "Dark Energy" concept be wrong?

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  39. RogerWaters

    B Why doesn't cosmic inflation violate conservation of energy?

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  40. S

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    Question
  41. S

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  42. R

    I Kinetic Energy derivation assumption?

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  43. S

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  44. benagastov

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  45. V

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  46. Question69

    B Is energy really not conserved in a constantly expanding Universe?

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  47. L

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  48. M

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  49. T

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  50. DrunkElk1601

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