Energy transfer Definition and 155 Threads

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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    Question about work and energy transfer

    Something is bugging me... Is there something wrong with thinking that if an object A exerts a constant force F on object B, through a distance d, then A transfers F*d joules of energy to B? Consider a situation in space... an astronaut mass m, and a rock m (no other objects anywhere). The...
  2. C

    How does radiation transfer its energy to matter?

    I'm a bit confused about the way radiation is said to 'transfer' its energy to matter. I must be looking at it the wrong way, so I'd appreciate it if someone could explain what I am missing. I don't see how energy is transferred to atoms through ionization. The way I see it is charged...
  3. G

    Explaining Energy Transfer on Earth

    just a quick query, i hope you physics folk can explain If all of the energy that enters Earth comes form EM waves from the sun and once inside the atmosphere the waves change into all different forms of energy (ie heat Ek electrical). Doesnt it make sense to prevent a build up of energy in...
  4. C

    Unlock the Mystery of Kinetic Energy Transfer with Magnets!

    Check this site address out: http://scitoys/scitoys/scitoys/magnets/gauss.html It is a neat little science project site, and I found this project the most interesting (except for the non-elecricity requiring radio) on their site. How it tells you it works(shortened): You take a ruler and...
  5. F

    What Is the Energy Transfer Mechanism in Waves and Sound?

    Ah...yet more questions... These are some questions from my last assignment for the semester- I figured I would finish it all up before I head off the competitions for the next month. Again- I feel fairly confident with my answers- but I have had so much trouble in physics that I sometimes...
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