The conservation of energy
The capacity of a system to do work or the quantity required for mechanical work to take place. Measured in joules (J). For example, a man transfers 100 J of energy when moving a wheelbarrow. can be transferred usefully, stored or The spreading out and transfer of energy stores into less useful forms, such as thermal energy causing the surroundings to heat up. Dissipated energy is often referred to as 'wasted' energy, since it is not transferred to a useful output. , but it cannot be created or destroyed.
In all cases, energy comes from one store and is transferred to another store. This means that all the energy in the universe was present at the The scientific theory that describes the early development of the Universe. and will still be around at the very end of time.
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Examples of conservation of energy
The skydiver
When a skydiver jumps out of a plane, he begins to lose energy from the The energy stored by an object lifted up against the force of gravity. Also known as GPE. as his height decreases, and his kinetic energy store increases as his speed increases.
However, not all of the energy lost from the gravitational potential energy store is transferred into the Energy which an object possesses by being in motion. . As some work is done pushing against the air particles, some of the gravitational potential energy is transferred to the air particles and is stored as The total kinetic energy and potential energy of the particles in an object..
Smartphones
All smartphones contain a battery that stores chemical energy. When a smartphone is in use, the battery's chemical energy store decreases. The energy is transferred via the electrical work pathway to light the screen and produce sound.
The light that comes from a smartphone is emitted via the light radiation pathway, and the sound waves are produced by a speaker that vibrates back and forth and are emitted via the sound radiation pathway. Eventually both the light and the sound pathways lead to (very small) increases in the internal energy store (temperature) of the surroundings.
In addition to this, many smartphones also heat up when used, so energy from the A type of stored energy. It is taken in when chemical bonds break, and given out when chemical bonds are made. is also transferred to the internal energy store. This causes an increase in the temperature of the phone and causes it to emit more energy via the infrared radiation pathway.