Energy Flashcards
What is elastic energy?
Elastic potential energy is stored when an object is stretched or squashed eg. compressed springs, inflated balloons.
What is kinetic energy?
Kinetic energy is the energy of a moving object. Eg. Runner, Buses.
What is thermal energy?
- The total kinetic and potential energy of particles in an object.
- This is in the vibrations of the object - Kinetic energy.
- Increasing separation of molecules requires work to be done by the potential energy store.
- In hotter objects, they have more thermal energy and vibrate faster.
What is chemical energy?
- Energy stored in chemical bonds.
- Can release energy by a chemical reaction. Eg. Food, Fuels, Batteries.
What is nuclear energy?
- Energy stored in the nucleus of an atom.
What is electrostatic energy?
- Energy sored when repelling charges move closer together or when attracting charges are pulled further apart.
What is magnetic energy?
- Energy stored when repelling poles are pushed closer together and attracting poles move further apart. eg. a fridge magnet, maglev trains.
What is mechanical work?
- Mechanical work is a force moving an object through a distance.
What is electric work?
- Electric work is when charges are moving due to a potential difference.
What is voltage?
- Voltage is the measure of energy given to charge carriers.
What is potential difference?
- Potential difference is the voltage between two points that make an electric current flow.
What is heating?
- Heating is an energy transfer due to temperature difference caused electrically or by a chemical reaction.
What is radiation?
- Radiation is energy transferred by waves. eg. light, infrared radiation emitted from the sun.
What are energy flow diagrams?
- Energy flow diagrams show how energy is transferred from one store to another.
What is work?
- Work is the measure of energy transfer when a force moves an object through a distance.
What are work done and energy transferred measured in ?
- Work done and energy transferred are measured in Joules.
What is power?
- Power is the rate energy is transferred per second.
What is the equation for work done?
- Word done = force x distance
What is the equation for power?
- power = work done/ time
What is efficiency?
Efficiency: How good a device is at transferring energy input to useful energy output.
What is the equation of efficiency?
Efficiency = useful energy transferred/ total energy supplied x 100 .
How many milijoules are in a joule?
- A millijoule is 0.001J. so 1/1000 of a Joule.
How many kilojoules are in a joule?
- 1000J in a kilojoule.
What is “The Law of the Conservation of energy?”
- The Law of Conservation means that the total energy before transfer is the same as the total energy after transfer because it cannot be created/ destroyed.
Who is the “Joule” named after?
- The Joule is named after James Prescott Joule (scientist.)
Give two examples of energy transfer diagrams.
- Transfer diagram.
- Sankey diagram.
What does it mean if energy is dissipated?
- Dissipation is the transfer of energy stores into less useful ones. Known as “wasted” energy.
Why is a lubricant used?
- Lubricants are used to reduce the amount of friction, therefore decreasing the thermal energy.
- Energy will not be dissipated.
Why are LED lights more efficient than filament lights?
- They are energy efficient, producing less heat (dissipated energy.)
Give an example of energy dissipation.
- Electrical work in tumble dryers.
- Transferred to useful thermal energy.
- Dissipated into sound waves
What is the calculation for the amount of kinetic energy?
Kinetic energy = 1/2x mass x speed (squared)
When using the formula for kinetic energy, what is the measure of mass?
- The measure of the mass is Kg.
How much kinetic energy does a 30 kg dog have when it runs at 4 m/s?
- 240J
What is the formula for the calculation of kinetic energy?
Ek = 1/2mv(squared.)
What is a renewable energy source?
- A renewable energy source is one that is being (or can be) replenished as it is used.
Give two advantages of renewable energy resources.
- Renewable energy will never run out.
- Once in place, will not add CO2 to atmosphere, not contributing to climate change.
Hydroelectric power is very reliable, so what is the issue with it?
- Many habitats are destroyed when building them.
- Only suitable in countries with a lot of rivers, not the UK.
What is geothermal energy?
- Geothermal energy is using the heat from the earth to generate electricity.
What is a fossil fuel?
- A fossil fuel is a finite resource that releases energy.
What is the difference between temperature and thermal energy?
- Temperature is how cold/ hot something is. Depends on how fast particles are moving.
- Thermal energy - The more particles (larger it is) more the thermal energy.
What is heat?
- Heat is the transfer of thermal energy from a warmer object to a colder object.
What is thermal energy affected by and why?
- Mass and size.
- Total amount of kinetic + potential energy.
- The bigger it is , the more thermal energy it has because it has more particles.
