P1 - Energy Flashcards
Give eight energy stores.
Thermal energy Kinetic energy Gravitational potential energy Elastic potential energy Chemical energy Magnetic energy Electrostatic energy Nuclear energy
What is a system?
The object or group of objects that you are investigating
What is a closed system?
A system where neither matter or energy can enter or leave
What is the net change in the total energy of a closed system and why?
0 because no energy can get in from outside the system or escape from the system
Give two ways in which energy can be transferred.
Heating
Doing work
If an object is moving, what type of energy does it have?
Kinetic energy
If an object is raised, what type of energy does it have?
Gravitational potential
When an object falls, what energy transfer happens?
Energy from the object’s gravitational potential energy store is transferred to its kinetic energy store
How do you calculate the gravitational potential energy of an object?
mass x gravitational field strength x height
What energy transfer happens as a result of air resistance when an object is falling?
Energy from the object’s gravitational potential energy store is transferred to its thermal energy store
If an object is stretched, what type of energy does it have?
Elastic potential energy
How do you calculate the elastic potential energy of an object?
1/2 x spring constant x extension^2
How do you calculate the kinetic energy of an object?
1/2 x mass x speed^2
What is specific heat capacity?
How easily something heats up and cools down
If a material has a high specific heat capacity, what does that mean?
A lot of energy is required to heat the material
If a material has a low specific heat capacity, what does that mean?
Not very much energy is required to heat the material
How do you calculate the specific heat capacity of a material?
change in thermal energy / mass / temperature change
What is the conservation of energy principle?
Energy can never be created or destroyed
What is power?
The rate of energy transfer
What is power measured in?
Watts
How do you calculate power?
energy transferred or work done / time
Give two ways in which unwanted energy transfer can be reduced.
Lubrication
Thermal insulation
How does lubrication reduce unwanted energy transfer?
It reduces the friction between two objects that are rubbing together
Why are lubricants usually liquids?
Liquids can flow easily between objects, so the objects will be coated in the lubricant
What happens to the particles of an object when it is heated?
The particles vibrate more and collide with each other
How does energy transfer by conduction occur in solids?
When particles collide with each other, energy is transferred between them
How does energy transfer by convection occur in liquids and gases?
When particles near the source of energy are heated, their density decreases. The less dense regions rise above the denser regions, which are pushed closer to the source of energy
How do you calculate efficiency?
useful energy transfer / total energy transfer
Give three ways in which the efficiency of an energy transfer can be increased.
Insulation
Lubrication
Streamlining
What are the three main fossil fuels?
Coal
Oil
Natural gas
Give two non-renewable energy resources.
Fossil fuels
Nuclear fuel
Give two nuclear fuel sources.
Uranium
Plutonium
Give six renewable energy resources.
Solar Wind Hydroelectricity Biofuel Tides Geothermal
How are fossil fuels used to provide energy?
They are burnt
How is the wind used to provide energy?
The wind turns turbines which generate electricity
How is the Sun used to provide energy?
Solar cells generate electricity directly from sunlight
How does geothermal power work?
The heat from hot rocks, which can be found in volcanic areas, is used to generate electricity
How does hydroelectric power work?
Falling water passes through turbines which generate electricity
How are biofuels used to provide energy?
Biofuels (plant products or animal waste) are burnt to generate electricity
