Physics energy stores

• Energy cannot be created or destroyed. it can be stored or transferred
• Chemical energy- energy stored in chemical bonds, food and batteries
• kinetic energy- energy can be stored in moving objects
• gravitational potential energy- energy stored by an object because of its height above the ground
• Thermal energy- energy stored in hot objects
• Elastic energy 


  Stored in stretched or compressed materials
• Atomic energy 


  Energy stored in atoms
• Wasted energy 


  dissipates to the surrounding area
• energy stores cant be fixed instead can be transferred
• Energy stores can be transferred either mechanically or electrically heating or radiation
• particular object or groups of objects we can call this a collection of matter a system
• When a system changes energy is transferred between objects or between different forms
• Opens systems is when the matter of the system can exchange energy with outside of the system, can lose or gain energy by interacting with the outside world
• A closes system is separate from the outside and even though energy can be transferred through the system. overall change = 0
• Energy transferred can also be known as work done
• Mechanical= use a force to move an object kicking ball in the air
• Electrical when current flows, energy required to overcome resistance in the wires
• Chemical when chemical reaction occurs, energy released during combustion
• Not all devices are 100% efficient
• Efficiency= proportion of ener supplied transferred to useful energy
• Efficiency = useful energy/ total energy input ( x 100 if needed as % )
• Useful energy= efficiency x total energy( efficiency has to be % )
• Sankey diagrams always show efficiency visually and they are used to represent energy transfers
• Total energy= useful energy/ efficiency
• To prevent the dissipation of thermal energy you can use insulators
• Devices waste energy for various reasons e.g electrical resistance, unwanted sound energy and friction
• To reduce useful energy being wasted between moving parts of a machine caused by friction and increase amount of useful energy you can use lubricants
• Law of conservation equation

  energy at end + wasted energy = energy at the start