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
