What actually energy is?
Answers:
energy, in physics, the ability or capacity to do work or to produce change. Forms of energy include heat, light, sound, electricity, and chemical energy. Energy and work are measured in the same units—foot-pounds, joules, ergs, or some other, depending on the system of measurement being used. When a force acts on a body, the work performed (and the energy expended) is the product of the force and the distance over which it is exerted.
Potential and Kinetic Energy
Potential energy is the capacity for doing work that a body possesses because of its position or condition. For example, a stone resting on the edge of a cliff has potential energy due to its position in the earth's gravitational field. If it falls, the force of gravity (which is equal to the stone's weight; see gravitation) will act on it until it strikes the ground; the stone's potential energy is equal to its weight times the distance it can fall. A charge in an electric field also has potential energy because of its position; a stretched spring has potential energy because of its condition. Chemical energy is a special kind of potential energy; it is the form of energy involved in chemical reactions. The chemical energy of a substance is due to the condition of the atoms of which it is made; it resides in the chemical bonds that join the atoms in compound substances (see chemical bond).
Kinetic energy is energy a body possesses because it is in motion. The kinetic energy of a body with mass m moving at a velocity v is one half the product of the mass of the body and the square of its velocity, i.e., KE = 1/2mv2. Even when a body appears to be at rest, its atoms and molecules are in constant motion and thus have kinetic energy. The average kinetic energy of the atoms or molecules is measured by the temperature of the body.
renewable energy can be used time and again, such as wind power or hydro plants, non renewable is like oil or coal where once it is burned it is gone forever
http://en.wikipedia.org/wiki/energy.
well energy is defined as the ability to work
but energy is no reusable but it is lost as heat
renewable energy is one which never go lost,you can use it in another form @different time,like solar,...
Renewable energy is the kind that we can use on and on, along all the lifetime of humanity and there are many kinds:
-Biomass-Sugar Cane, Wood or Beet Alcool, Oils coming from Grains, Methane Gas from garbage, Coal from wood etc..
-Hydroelectric Power
-Solar
-Geothermal
Second kind the ones that will end in our lifetimes or before human existence:
-Oil- There will be for no more than 100 years
-Gas- No more than maybe 200 years
-Coal-Will last much longer but there is also a limit.
On second thought, all forms of energy comes from the Sun(or the Stars) without exception.
The Biomass needs the sun.
Rivers needs the Sun to survive or else they will freeze.
Oil, gas and coal came from ancient Biomass so.
The Earth came from the Sun or the Stars so Geothermal energy also.
try class 6th books mann
You question title is a little misleading, i'll assume you are talking about sources of energy that we utilise and not the nature of energy itself.
You can find this out in any high school science book, it sounds like you trying to get someone else to do your homework.
Renewable energy sources are those that do not reduce the natural resources on the planet. e.g wind, hydro-energy, solar energy.
Non-Renewable energy forms are those which consume the earths natural resources such as gas, coal, oil etc.
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