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Energy Transfer and System - Coggle Diagram
Energy Transfer and System
Energy is transferred between stores
1) Kinetic energy stores (KE %3D Yomv, p.156)
2) Thermal energy stores 3) Chemical energy stores
4) Gravitational potential energy stores (AGPE = mgh, p.156)
5) Elastic potential energy stores 6) Electrostatic energy stores
7) Magnetic energy stores
8) Nuclear energy stores
Energy can be transferred between stores mechanically (by a force doing work - see next page). electrically (by a moving charge doing work). by heating or by radiation (e.g. light or sound).
When a system changes, Energy is transferred
A System is just a fancy word for a single object or a group of objects that you're interested in. You can define your system to be anything you like.
When a system changes, energy is transferred (p.157). It can be transferred into or away from the system, between different objects in the system or between different types of energy stores.
Whenever a system changes, some energy is dissipated and stored in less useful ways (p.158).
How you define your system changes how you describe the energy transfers that take place (see below).
A closed system is one that's defined so that the pat change in energy is zero (p.157).
Energy can be transferred by Heating
A pan of water is heated on a gas camping stove.
When the system is the pan of water, energy is transferred into the system by heating
to the thermal energy stores of the pan and the water, which increases their temperature.
When the system is the camping stove and the pan, energy is transferred from the chemical energy store of the gas to the thermal energy stores of the pan and the water, increasing their temperature.
Energy can be transferred by doing work
A box is lifted up off of the floor. The box is the system.
As the box is lifted, work is done against gravity.
This causes energy to be transferred to the box's kinetic and gravitational potential energy stores.
Energy can be transferred by electrical equipment
Electric devices work by transferring energy between different energy stores