P1 - Energy Flashcards
Kinetic energy is:
The energy stored in moving objects
Elastic potential energy is:
The energy stored in an elastic object when work is done on the object
Gravitational potential energy is:
The energy stored in an object due to its position above the Earth’s surface
Specific heat capacity is:
The amount of energy required to raise the temperature of 1kg of the substance by 1•C
Conservation of energy
Energy can be transferred usefully, stored or dissipated but it cannot be created or destroyed.
Energy transfers: Pendulum
• At the top - the mass has the maximum store of GPE
• As it swings - GPE transferred to KE
• At the bottom - the mass has the maximum store of KE
• As it swings back up - KE transfers to GPE
Reducing unwanted energy transfers: Pendulum
Reduce friction by:
• Using a lubricant on the fixed point
• Remove the air particles around the pendulum
Work is done when:
Energy is transferred from one store to another
Define Power
The rate at which energy is transferred/ the rate at which work is done
Describe ways to increase the efficiency of an energy transfer (Heating water)
• Use a pan with wider base & a lid
• Place the heating element inside the water
• Use material with lower thermal conductivity (plastic)
Define Thermal conductivity
The higher the thermal conductivity of a material, the higher the rate of energy transfer by conduction across that material.
Reducing thermal energy transfer from a house can be done by:
Constructing the building using materials with a low thermal conductivity.
Build the house with thick walls
State the main fossil fuels used for energy
• Coal
• Oil
• Gas
Advantages of using fossil fuels
• Reliable
• Release lots of energy
• Abundant & cheap
• Versatile
Disadvantages of using fossil fuels
• Releases lots of carbon dioxide
• Non-renewable
• Releases pollutants
Advantages of Nuclear power
• Once a power plant is running, no carbon dioxide is released
• Extremely reliable
Disadvantages of Nuclear power
• Contain highly dangerous radioactive materials
• Decommissioning a nuclear power plant takes many years and is expensive
• Generates large amounts of highly dangerous radioactive waste - must be stored for 1000s of years before It’s safe
Renewable energy resources are:
Resources that can be replenished as it is used
Advantages of renewable energy resources
• Never run out
• Once in place, they do not add any carbon dioxide to the atmosphere
Why are wind and solar power unreliable?
Wind - Some days are not windy
Solar - does not work well on cloudy days
What are the positives & negatives of hydroelectric power?
Positive:
• Very reliable
Negative:
• Habitats are destroyed when dams are built
• Only useful in countries with lots of rivers
Tidal power is (1) however (2)
1) Extremely reliable
2) The UK does not generate any electricity from tidal power currently
Wave power is (1) however (2)
1) Reliable and has huge potential in the UK
2) Small scale & experimental currently
Geothermal energy is (1) but (2)
1) Reliable - uses heat from the earth to generate electricity and heat buildings
2) Not really used much in the UK
Problems with Renewable energy:
• Lots of energy used in the UK is for transport.
Almost all cars in the UK run on petrol or diesel which are fossil fuels.
What are the positives and negatives of Biofuels?
Positives:
• Produced from plant materials.
Burning biofuels does not add extra carbon dioxide into the atmosphere (carbon neutral)
• Very useful - can be used to power vehicles
Negatives:
• If land is used to grow crops for fuel, food prices could be pushed up
