Energy Flashcards
(23 cards)
A system is
An object or a group of objects
When a system changes
Change in energy stores
Sankey diagrams
.
Kinetic energy
0.5 x mass x speed^2
GPE
Mass x gravitational field strength x height
Elastic potential energy
0.5 x spring constant x extension^2
Internal energy
Total kinetic energy and potential energy of all the particles that make up a system
Doing work on a system increases
The energy stored in a systems
Heating changes the
By increasing the
Energy stored in a system
Energy of the particles within it
As the energy increases
Either increase. Or.
The temperature or produce a change of state
If the temperature increases , the increase depends on
The mass of a substance heated
What the substance is
The energy input
Specific heat capacity is
The amount of energy required to raise the temperature of 1kg 1degree
Specific heat capacity formula
Change in thermal energy=mass x specific heat capacity x temperature change
Required practical
Pg27
Energy can either be
Transferred usually
Stored
Dissipated
In a closed system
Total energy never changes
But it can be transferred from one store to another
Energy cannot be
Created or destroyed
Wasted energy is caused by
Unwanted energy transfers
Unwanted transfers can be reduced in several ways:
Lubrication=reduces the friction that produces heat
Tightening any loose parts=prevents unwanted vibrations that wastes energy as sound
Thermal insulation=reduces heat loss
A building wastes energy when
It loses heat to the surroundings causing it to cool down
Yeh rate of cooling depends on
The thickness and thermal conductivity of the walls
Thin wallls with high thermal conductivity will
Conduct heat the quickest and the building will cool down rapidly
Non renewable and renewable energy
Pg 29
