Changes In Energy Stores Flashcards
Name the 8 different energy stores
- thermal (heat)
- kinetic
- gravitational potential
- elastic potential
- chemical
- magnetic
- nuclear
-electrostatic
Name the 4 energy pathways
- mechanically (when work is done)
- electrically (by moving charges)
- heating
- radiation (light or sound)
Describe the energy transfer during a person throwing a ball upwards in the air in two steps
- the person throwing the ball upwards does WORK on the ball
- energy is transferred from the CHEMICAL STORE of the muscles of the persons arm to the KINETIC STORE of the ball
Describe the change in the energy stores when the ball moves upwards
- as the ball moves upwards gravitational potential Store INCREASES and the kinetic store DECREASES
From the ball being thrown upwards, some energy is left where is that energy now transferred and how?
Some energy is transferred to the THERMAL STORE of surroundings by HEATING due to air resistance
At the top of the flight of the ball, compare the difference of the energy stores
At the top of its flight the GRAVITATIONAL POTENTIAL store is filled and the KINETIC STORE is now empty
Describe the energy transfers in a car slowing down in two steps.
- work is done by friction between the brakes and the wheels
- energy is transferred from the kinetic store of the wheels to the thermal store of the wheels and the surroundings
Describe the energy transfers when boiling a kettle in 4 steps
- energy transferred electrically to the heating element of the kettle
- energy is transferred by heating to the water from the element
- thermal store of the element decreases+ the thermal store of the water increases
- some energy is transferred to the thermal store of the surroundings
Describe the energy transfer of a moving vehicle hitting a stationary object in 3 steps.
- work is done by the normal contact force between the moving and stationary objects
- energy is transferred from the kinetic energy store of the moving object to the thermal stores of both the vehicle+ object aswell as to surroundings
- sone energy will be transferred away to the thermal store of the air by sound waves
What happens when energy is transferred from store to store?
It is dissipated
Define dissipated
It is no longer concentrated in one store it is more spread out
Where is the dissipated energy transferred to generally in an open system?
Transferred to the thermal store of the environment
What is the law of conservation of energy?
Energy can be transferred usefully, stored or dissipated but CANNOT BE CREATED OR DESTROYED
Define mechanical work
A force moving an object through a distance
Define electrical work
Charges moving due to a potential difference
Define heating as an energy transfer
Due to a temperature difference causes electrically or by chemical reaction
Define radiation as an energy transfer
Energy transferred as a wave (example: light+ infrared)
What happens to any energy that is not transferred to the useful energy stores?
Wasted because it is lost to the surroundings
Describe why adding a lubricant between two surfaces is an advantage when trying to avoid energy dissipation
Adding lubricant between the two surfaces reduce the friction when rubbed together and so less heat is wasted
What other way can energy be dissipated into the surroundings besides heating?
Sound waves
Kinetic energy= 1/2* mass* speed squared, what are the units for each of these?
Kinetic energy= Joules (J)
Mass= kilograms (kg)
Speed= metres per second (m/s)
Elastic potential energy= 1/2* spring constant* extension squared, what are the units for each of these?
Elastic potential= Joules (J)
Spring constant= newtons per meter (N/m)
Extension= metres or cm (m) (cm)
Gravitational potential energy= mass* gravitational field strength* height, what are the units for each of these?
-Gravitational potential= Joules (J)
-Mass= Kilograms (kg)
-Gravitation field strength=
newtons per kilogram (N/kg)
-Height= metres (m)
Define the kinetic energy store
Energy stored in an object that is moving
Define the magnetic energy store
Energy stored by two magnets attracting or repelling one another
Define the thermal energy store
Energy stored in an object due to the heat of the object
Define the chemical energy store
Energy stored by chemical bonds
Define the elastic potential energy store
Energy stored by an object that has been stretched or compressed
Define the gravitational potential energy store
Energy stored by an object when it’s lifted in height
Define the nuclear energy store
Energy stored in the nuclei of atoms
