SP3 - Conservation of Energy ✓ Flashcards
(30 cards)
SP3a - By what processes can energy be transferred?
- Heating
- Forces
- Electricity
- Light
- Sound
SP3a - What are the 9 energy stores?
- Kinetic
- Thermal
- Gravitational Potential
- Elastic Potential
- Sound
- Light
- Chemical
- Nuclear
- Electrical
SP3a - What diagram might you use to display the transfer of energy?
A sankey diagram, The width of the bars represent the amount of energy.
SP3a - What is the law of the conservation of energy?
- Energy cannot be created or destroyed, only transferred between stores.
- In a closed system, the total start energy = the total end energy
SP3a - What is unit for measuring energy?
Joules (J)
SP3b - How do you calculate efficiency?
total useful energy output / Total energy input Efficiency is on a scale of 0 to 1. To calculate it s a percentage, x100
SP3b - How do you distiguish useful and wasted energy on a sankey diagram?
The useful energy has an arrow going staright while the wasted energy arrow turns off.
SP3b - What is it called when energy transfers to its surroundings by heating?
Dissipation
SP3b - What is the most common form of wasted energy?
Thermal
SP3b - What might you do to moving parts to reduce energy loss and why?
- Use a lubricant.
- Moving parts cause friction which causes energy to dissipate losing energy.
- Lubrication reduces friction and thus energy loss by friction.
SP3c - What are the 3 different ways in which energy is transferred by heating?
- Convection - This is when part of the fluid that is warmer than the rest rises up and creates a convection current
- Conduction - This is when vibrations are passed on between particles in a solid
- Radiation - The only way in which energy can be transferred through a vaccuum. Infrared radiation can also pass through gases and some solid materials.
SP3c - How is a flask able to maintain the temperature of its contents?
- Silver coating on the outside and inside reflects radiation which would transfer thermal energy
- Glass walls with vacuums between create a cavity stopping heat from entering or escaping
- Plastic stopper stops heat from escaping
SP3c - Why do cavities in walls help insulate a house?
- It creates an air gap - air has a very low thermal conductivity. When air is trapped, it cannot form convection currents and so does not transfer much energy
SP3c - What factors affect the rate of which energy is transferred through a material by heating?
- The material’s:
-
Thickness
rate of energy transfer is reduced by increasing thickness -
Thermal Conductivity
rate of energy transfer is reduced by decreasing thermal conductivity -
Temperature Difference across it
rate of energy transfer is reduced by decreasing temperature difference
SP3d - As an object falls describe the change in energy stores in terms of GPE and KE.
- As an object looses height, it looses GPE this ‘lost’ energy transfers, mostly, into kinetic energy as it is moving.
- Some other energy may transfer into sound energy
SP3d - What is the formula for change in gravitational potential energy.
ΔGPE = m x Δh x g
(change in GPE is mass x change in height x gravitational field strength)
SP3d - What is the formula for Kinetic energy?
KE = ½ x m x v²
(Kinetic energy = mass x velocity² divided by 2)
SP3d - What is the gravitational field strength on earth?
9.81 (Can be rounded to 10) m/s² or N/Kg
SP3e - Apart from the lack of sustainability, why is burning fossil fuels not beneficial?
It releases Carbon dioxide and other gases that are harmful for the environment as they contribute to climate change.
SP3e - What are the four main types of non-renewable energy sources?
- Fossil fuels:
- Natural gas
- Coal
- Oil
- Nuclear
SP3f - What are the pros and cons of biofuel?
Pros:
- Will never run out
- Carbon neutral (Burning fuels releases carbon put planting plants took in carbon so its neutral)
Cons:
- Energy is also needed to grow and harvest the crops and to turn them into fuel - so most bio fuels aren’t really carbon neutral
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SP3f - What are the pros and cons of hydroelectric energy?
Pros:
- Very reliable
- Will never run out
- Won’t release carbon dioxide once installed
Cons:
- Habitats destroyed
- Only useful when water sources are nearby
SP3f - What are the pros and cons of Tidal energy?
Pros:
- Avaliable at predictable times
- Will never run out
- Doesn’t contribute to climate change
Cons:
- Some argue that it harms wildlife
SP3f - What are the pros and cons of using solar panels and solar energy?
Pros:
- Will never run out
- Won’t release carbon dioxide once installed
Cons:
- Energy output depends on sun and so may not always be available
