Luci's notes Flashcards
energy
Energy:
* The capacity or ability to do work, or the capacity to be able to do work
* Everything possess energy
* We encounter and use it every single day
* All energy originates from the sun
Energy can be transformed and transferred. Energy cannot be destroyed or created it can only be transferred or transformed
potential energy
Potential energy is that is stored and has potential to turn into different types of energy. e.g. a rock on the top of the hill, it has the potential to roll down the hill because of its position and mass. Potential energy is the stored energy within the object due to its position, arrangement or state. The object has the object to do something, when the position, arrangement or state of the object changes. e.g. a stretched rubber band, a rock on the top of a hill.
kinetic energy
Kinetic energy is energy of motion. Any object in motion or movement has kinetic energy. e.g. a moving car, a waterfall, a yo-yo
types of energy
- Energy can be stored in many forms and can be transferred between these forms
kinetic energy
- Action energy, used to describe things that are moving
- It is the energy an object possess due to its motion/movement
- This includes very large things like plantes, and very small one, like atoms
- The heavier an object is, and the faster it moves, the more kinetic energy it has
1. Sound energy - energy from sound vibration
2. Heat (thermal) energy - energy due to the movement of atoms and molecules within a solid, liquid or gas
3. light (radiant) energy - energy of electromagnetic waves which is mitted by the sun and globes
4. Electrical energy - energy possessed by electrons when moving through a circuit
5. Translational kinetic energy - the energy in a moving object
potential energy
- Stored energy that is waiting to be released
- Comes in a variety of types
1. Gravitational potential - the energy due to the height above the ground, when an objected is lifted up, it gains energy (GPE)
2. Elastic potential - the energy in a stretched elastic object
3. Chemical potential - the energy stored in chemical bonds
4. Nuclear potential - energy stored inside the nucleus of an atom
5. Electrical energy - energy possessed be electrons
6. Magnetic energy - energy possessed by objects with opposite charge that are separated
electrical energy
Electrical energy can be both categorised as potential and kinetic energy
Energy Transfers and Transformations
The law of conservation of energy:
Energy cannot be created or destroyed. But only changed from one form into another form.
Energy can only be transferred and transformed, energy cannot be destroyed or created.
Energy cannot be created or destroyed. Instead, it is transferred between objects (transfers) and changed into different forms (transformations)
The difference between transfers and transformations between energy is that Transfers, transfer the same type of energy from one object to another, whereas transformations between energy change the shape or form and the type of energy that is being passed from one object from another.
Coal - light in a classroom
Coal is burnt —> passes through wires —-> light bulb
Chemical energy —–> electrical energy —-> light energy \ thermal energy
good to remeber
The amount of energy you start with will always equal the amount of energy you end with.
measuring energy
Energy is measured in Joules, or capital ‘J’. Joules is the SI unit - the agreed upon unit of measurement for energy.
converting
Energy from Joules to kilojoules to megajoules.
1 kJ = 1,000 J
1 MG = 1,000,000 J (106) ÷1,000,000
1 MG = 1,000 kJ (103) ÷1,000
When converting from a smaller unit to a larger unit. Divide. If converting from a larger unit to a smaller unit. Multiply.
1 kilojoule or kJ = 1000 Joules J - to convert Joules to Kilojoules divide by 1000. in the same instance to convert Kilojoules to Joules multiply by 1000
A Megajoule or MJ is 1,000,000 joules. This is the same as 1000kJ.
MG to kJ to J
MG to kJ = MG multiplied by 1, 000
MG to J = MG multiplied by 1,000,000
J to MJ = J divided by 1,000,000
kJ to MG = Kg divided by 1,000
useful and waste energy
Waste energy is any unwanted energy forms that are produced in an energy transformation. Useful energy is the intended product of an energy transformation. Applications that produce less waste energy are more efficient.
what symbol is used to represent efficiency
They symbol ‘e’ is used to represent efficiency.
sankey diagram
You are able represent energy efficiency in a SANKEY diagram. Sankey diagrams are a visualisation of the energy flow process. It represents three things, the total energy in, the wasteful energy and the useful energy. The height of the box represents the amount of energy.
what does this diagram represent
This type of diagram represents the Law of the conservation of energy as the total amount of energy put in is transformed into different types - some useful, some wasteful. The total sum of the energy useful and wasted is equal to the amount of energy in.
The amount of energy in = useful energy + wasted energy.
e.g. 100 J = 65 J + 35 J
