ENERGY Flashcards
what is a system
an object or group of objects
Students should be able to describe all the changes involved in the way energy is stored when a system changes, for common situations.
For example:
• an object projected upwards
• a moving object hitting an obstacle
• an object accelerated by a constant force
• a vehicle slowing down
• bringing water to a boil in an electric kettle
• boiling in an electric kettle: electricity through the kettle increases the internal (thermal) energy of the element which in turn increases the internal energy of the water which increases the temperature of the water
• an object accelerated by a constant force
The boat pushes through the water as chemical energy is transferred into kinetic energy
a system can be changed by:
• heating
work done by forces •
work done when a current flows
the transfer of energy from a gravitational potential energy store to a kinetic energy store
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reducing unwanted energy transfers,
for example through lubrication and the use of thermal insulation.
An energy transfer of 1 joule per second is equal to a power of 1 watt.
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The higher the thermal conductivity of a material the higher the rate of energy transfer by conduction across the material.
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Changes of state are physical changes which differ from chemical changes because the material recovers its original properties if the change is reversed.
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Internal energy is the total kinetic energy and potential energy of all the particles (atoms and molecules) that make up a system.
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define what is meant by a closed system
no net changed to the total energy
closed system- where no energy can escape
explain why a pendulum that gradually stops spinning is not a closed system
it slows down and loses kinetic energy
energy is transferred OUT of the system
how is energy transferred?
due to work done by the forces
DO NOT FORGET
SQUARED WHEN WORKING OUT KE OR ANY ENERGY WITH SQUARED!!
Suggest a technique for finding the speed of an arrow
video analysis
where is energy transferred to a lot
THERMAL ENERGY OF THE SURROUNDINGS
