Energy Flashcards
Define energy
A property that can be transferred in order to perform work or cause heating effects
State the 8 energy stores
Chemical kinetic gravitational, potential, thermal, elastic potential, magnetic, electrostatic and nuclear
Name the 4 energy pathways
Heating, electrical, radiation and mechanical
Define system
An objects or group of objects that interact
Define open system
A system in which energy and matter can enter and exit eg a cup of tea
Define closed system
A system in which energy can enter and leave, but not matter, e.g. a cup of tea with a lid
Define an isolated system
A system in which neither energy or matter can enter or exit e.g. the universe
State the law of energy conservation
Energy cannot be created or destroyed, it can only be stored, transferred between stores or dissipated
State the units used to measure energy
J or joules
State why energy transfer is equivalent to work done
Because work must be done to transfer energy from one store to another
State when energy is stored in a kinetic store
When an object with mass is moving
Write an equation that links kinetic energy, mass and velocity
0.5 x mass x velocity2
Name two factors that affect the energy stored in the kinetic store of an object
Mass and velocity
Does mass of velocity have a greater impact on the energy stored in the kinetic store?
Velocity because it is squared
What is an elastic object
One that returns to its original shape and size when the force has been removed
When is energy stored in an elastic potential energy store?
When an object has been deformed, stretched or compressed
Write the equation linking elastic potential energy, spring, constant, and extension
Elastic potential energy = 0.5 x spring constant x extension2
State what is meant by extension?
The change in length, i.e. new length - original length
Name two factors that affect the energy stored in elastic potential store
Spring, constant and extension
Does extension of a spring constant have a great impact on the energy in the elastic potential store
Extension as this is squared
States, when is energy stored in a gravitational, potential energy store
When object with mass is raised above ground level
Write the equation linking gravitational, potential energy, mass and gravity and height
Gravitational potential = mass X gravitational field strength X height
Why when we calculate energy transferring between stores make 100% of the energy transfer not matter how many into the second store?
Because some of the energy is dissipated to the surrounding causing an increase of energy in the thermal store of the surroundings
State when energy is stored in the chemical energy store
Energy is stored in chemical bonds. Most example, includes fuels, such as batteries, food, petrol, wax, and oil.
State when energy is stored in a thermal energy store
When an object is at a temperature above, absolute zero - 273°C
