Energy Transfers Flashcards
(21 cards)
Define a system
A group of objects or an object
What is a closed system
Where matter or energy cannot leave or enter
What is conservation of energy
Energy cannot be destroyed or created
What are the 4 ways energy can be transferred between stores
Heating
Mechanically
Radiation
Electrically
What are 2 ways work is done
Mechanically - force moves an object
Physically - electric current
What is the formula for kinetic energy
0.5 x mass x speed (squared)
Define elastic potential energy
When something is squashed or stretched
What is the formula for elastic potential energy
0.5 x spring constant x extension(squared)
What is gravitational potential energy
Energy that is stored in an object because of its position in a gravitational field
What is the equation for gravitational potential energy
Mass x gravitational field strength x height
What is the formula for weight
mass x gravitational field strength
What is one way to calculate efficiency
Useful output energy/ total input energy
What is power
The rate energy is transferred
Give an equation for power
energy transferred/ time
What are the 8 energy stores
Magnetic Electrostatic
Thermal Kinetic
Elastic potential Nuclear
Gravitational potential
Chemical
What is the specific heat capacity
The amount of energy required to raise the temperature of one kilogram of the substance
What is the equation for Change in Thermal Energy
Mass × Specific Heat Capacity × Temperature Change
What is conduction and what are good conductors
This is the process by which energy is transferred through a material.
Metal
What is an insulator and what affects how insulating a material is
Materials that are poor conductors are known as insulators.
the thickness of the material or its thermal conductivity.
What does lubrication do
Reduces friction
Improves efficiency
How can you reduce energy lost from buildings
Double glazing
Loft insulation
