Energy (Seneca) Flashcards
What is a Kinetic store?
The energy stored by an object’s movement.
What is a Gravitational potential store?
The energy stored in objects raised above the Earth’s surface.
This energy exists because of the Earth’s gravitational field.
What is a Chemical store
The energy stored by the chemical bonds between atoms.
What is a Elastic potential store
The energy stored when an object is being stretched, compressed or squashed.
What is a Nuclear store
The energy stored in the nucleus of an atom.
The energy in the nuclear store can be released by radioactive decay.
What is a Internal (thermal) store?
The internal store of energy is the sum of the:
- kinetic energy stored in the particles of an object
- the chemical energy stored in chemical bonds between particles in the object.
Energy is added to your body’s 1. when you eat food.
Energy is stored there until you need it.
Your body then transfers it to your 2. when you need to keep warm, or to your 3. to move about.
- chemical store
- thermal store
- kinetic store
The amount of energy in an object’s internal energy is the …
sum (total) of the kinetic energy and potential energy stored in the object’s particles.
The temperature of a body (object) is a measure of the …
energy in the kinetic stores of its particles.
Increasing a body’s temperature increases the 1. , which means that 2.
- energy in the kinetic stores of the body’s particles
- the energy in the body’s internal store also increases.
kinetic energy=
1/2 ×mass(kg)×velocity(m/s)2
change in gravitational potential energy (J) =
mass(kg) ×gravitational field strength (N/kg) ×change in height (m)
The elastic potential energy (measured in joules) is equal to …
half the spring constant (in Newtons per metre) multiplied by the extension (in metres) squared.
v=
√(2E ÷ m)
Ee(j)=
0.5 x k (n/m)x e(m)2
E(m) =
√ ( 2Ee (j)/ k (n/m))
K (m) =
(2 x Ee (j)) / e (squared) (m)
Heating an object transfers energy to …
the object’s internal store of energy (the sum of the energy in the kinetic and chemical stores of its particles).
Energy transferred from one object to another via a force is an example of …
mechanical work
When an object falls from a building, the weight does …
mechanical work to transfer energy from the gravitational potential store to the kinetic store.
When you push a wheelchair, energy is transferred to the —– store of the wheelchair.
kinetic
———— can transfer energy from one object to another.
Light and other types of waves
An electrical current transfers ———from one object to another, such as a battery powering a torch.
energy
Methods of energy transfer:
- mechanical work
- electrical work
- heating
- waves
Which principle tells us that energy cannot be created or destroyed?
conservation of energy
Describe the energy transfer in a kettle.
Energy transfers from the electrical store of the mains power supply to the thermal store of the water.
Work is done …
by a force on an object.
Describe what happens to the energy when a object projected upwards
The object’s energy is initially in the kinetic store as it moves upwards.
The object’s energy is slowly transferred from the kinetic store to the gravitational potential store as it slows down and climbs higher.
Once the object reaches its highest point, all of its energy is in the gravitational potential store.
As the object falls again, energy transfers from the gravitational potential store to the kinetic store.
Describe what happens to the energy when an object accelerated by a constant force
Work is done by a force on an object.
This work is converted to the object’s kinetic store.
Describe what happens to the energy when a moving object hits an obstacle
The object’s energy is in the kinetic store at the start because it is moving.
When the object collides with the obstacle, energy is converted to:
The kinetic store of the obstacle (making it move).
The thermal store of the object and the obstacle (the particles in the object and the obstacle vibrate more).
Some energy remains in the object’s kinetic store as it moves away after the collision.
Describe what happens to the energy when water is brought to a boil in an electric kettle
Energy transfers from the electrical store of the mains power supply to the thermal store of the water.
Describe what happens to the energy when a vehicle slows down.
To begin with, the vehicle’s energy is in the kinetic store.
The brakes do work slowing the car down. During this process, energy is dissipated (lost) through heat and sound.
Heating an object increases the amount of energy in its ———- store.
internal
When an object is projected upwards, what store is its energy in at its highest point?
Gravitational potential
More work is done if you:
- push with the same force for a longer distance.
- push with a larger force for the same distance.
Work done(j) =
force (N) x distance (m)
work is the amount of …
energy transferred when a force moves something for example
Power (watts) =
Work done (j)/ time (s)
What is transferred to an object that has had work done on it?
Energy
work done=—————=change in energy
force×distance
work done=force×distance=
change in energy
The work done by a force is equal to the …
energy transferred to the object.
E=
VIt
The energy is equal to the potential difference multiplied by …
the current times by the time.
The energy is equal to the ————- multiplied by the current times by the ——-.
potential difference
time
Power is the …
rate of energy transfer (or work done).
The faster that energy is transferred (or work is done), the ———- the power.
higher
The power (measured in ———) is equal to the work done (in joules) divided by the time (in seconds).
watts
The power (measured in watts) is equal to the work done (in ———) divided by the time (in seconds).
joules
The power (measured in watts) is equal to the work done (in joules) divided by the time (in ———).
seconds
The more powerful a set of speakers is, the …
more sound energy will be produced.
The more powerful a lightbulb is, the …
more light energy will be produced.
The power (measured in watts) is equal to the work done …
(in joules) divided by the time taken (in seconds).
Car engines make a lot of noise and get hot when they are being used to move you about. Explain what happen to the useful and wasted energy.
- The useful energy store here is the kinetic store because you want the car to move you from one place to another.
- The heat and sound energy are wasted energy because they are of no use to you.
When wires are used in an electrical circuit, they heat up.
This is often not useful energy and so it is …
wasted (Dissipated)
In almost every energy transfer, friction creates heat energy and this energy is often…
wasted (Dissipated)
Efficiency =
(useful power output/total power input) x 100
The useful power output and total power input are measured in…
watts (W)
Efficiency =
(useful energy output/total energy input) x 100
The useful energy output and total energy input are measured in …
joules (J).
How is efficiency most often expressed?
As a percentage
To reduce the energy transfer, we might:
- Fit loft insulation (the roof).
- Use double glazing (windows).
- Use cavity wall insulation (walls).
- Fit carpets (floors).
We can decrease the rate a house cools down by:
- Having thicker walls.
- Having walls made from a material with a lower thermal conductivity.
The more heat that a material conducts (———————), the higher the rate of energy transfer by conduction across the material.
the higher its thermal conductivity is
The more heat that a material conducts (the higher its thermal conductivity is), the higher the …
rate of energy transfer by conduction across the material.
————- reduces frictional forces.
Lubrication
A moving object normally has at least one …
frictional force acting against it. This causes some energy to be dissipated.
Lubricants are normally …
liquids
Power (watts, W) =
energy transferred (joules, J) ÷ time (seconds, s)
Power (watts, W) =
work done (joules, J) ÷ time (seconds, s)
An energy transfer of 1 joule per second is equal to a power of …
1 watt
An —————————— is equal to a power of 1 watt.
energy transfer of 1 joule per second
The higher the thermal conductivity of a material the ———— the rate of energy transfer by conduction across the material.
higher
Ways to reduce unwanted energy transfers:
- lubrication
- thermal insulation
According to the principle of conservation of energy, …
energy cannot be created or destroyed, only transformed from one store of energy to another.
GPE lost =
mass × g × difference in height
What are methods through which the energy efficiency of the toy car could be increased?
- lubrication of the track
- design the car to be more aerodynamic
Lubricants reduce friction between the surfaces of objects that are …
rubbing together. They are normally in liquid form.
How do a air turbine work?
First, an energy resource is used to rotate a turbine.
The rotating turbine rotates a coil of wire in a magnetic field (a generator).
The coil of wire creates an electric current.
The electric current is an energy carrier (or pathway) that can take the energy to your home.
In most cases, to generate electricity, an energy resource rotates a …
turbine
———————— are burned to heat a fluid (water), which creates steam and turns a turbine.
Fossil fuels (such as coal and oil)
What are the disadvantages of fossil- fuel turbines?
- Not renewable.
- Inefficient.
- Contributes to global warming.
What are the advantages of fossil-fuels turbines?
- Reliable, on-demand electricity.
Fossil fuels (such as coal and oil) are burned to heat a fluid (water), which creates steam and turns a turbine. The turbine rotates, which …
turns a generator.
Some examples of fossil fuels are:
- coal
- natural gas
- oil
Fossil-fules are …
Non- renewable
In volcanic places, magma (underground lava) has lots of ————-. The magma heats rocks, which heat water in pipes. This rotates a turbine, which turns a generator.
internal energy
In volcanic places, magma (underground lava) has lots of ————-. The magma heats rocks, which heat water in pipes. This rotates a turbine, which ———
turns a generator.
In volcanic places, magma (underground lava) has lots of internal energy. The magma heats rocks, which ——————. This rotates a turbine, which turns a generator.
heat water in pipes
What are the advantages of Geothermal Energy turbines?
- Renewable.
- Reliable.
- Does not produce greenhouse gases.
What are the disadvantages of Geothermal Energy turbines?
- Can only be used where there is volcanic activity close to the surface.
- Geothermal plants can lead to the instability of the land surrounding it.
Explain generating and Transferring Energy
An energy resource rotates a turbine
The spinning turbine rotates a coil of wire in a magnetic field
An electric current is generated and this carries energy to your home
In magma, radioactive decay of substances like ———- heats heats up rocks which may heat the water.
uranium
When the wind blows, it rotates a wind turbine, which .
can turn a generator
What are the advantages of wind turbines?
- Source of renewable energy.
- They don’t take up much land space.
- Relatively low cost.
What are the disadvantages of wind turbines?
- Unreliable, only produces power when wind blows.
- Can be considered ugly or an eyesore.
- Can cause noise pollution.
What are the disadvantages of water turbines?
— Hydroelectric dams often change the paths of rivers, which can move people out of houses and harm local wildlife.
- Can be affected by droughts and variation in water flow over time.
- There are fewer and fewer suitable places to build a dam.
Water high above the ground is a ————————. Hydroelectric dams trap water. Allowing it to fall rotates a turbine, which turns a generator.
store of gravitational potential energy
Water high above the ground is a store of gravitational potential energy. ——————— trap water. Allowing it to fall rotates a turbine, which turns a generator.
Hydroelectric dams
Water high above the ground is a store of gravitational potential energy. Hydroelectric dams trap water. Allowing it to …
fall rotates a turbine, which turns a generator.
What are the advantages of water turbines?
- Renewable.
- More reliable than wind and solar.
- Capable of producing lots of energy.
One disadvantage of hydroelectric power is that the electricity used to pump water may have come from …
fossil fuel sources
The waves and tides in the sea are stores of ———- energy.
kinetic
Tidal and wave power use their kinetic energy to …
rotate a turbine, which turns a generator.
What are the advantages of tidal turbines?
- Renewable source of energy.
- Does not produce greenhouse gases.
- Tides are a predictable phenomenon.
What are the disadvantages of tidal turbines?
- The creation of tidal turbines can damage fragile ecosystems in estuaries.
- Does not produce electricity continuously.
- Turbines must be built close to the shore, affecting communities that live there.
The waves and tides in the sea are stores of ———— energy.
kinetic
Tidal and wave power use their kinetic energy to …
rotate a turbine, which turns a generator.
In a nuclear reactor, the nuclear energy stored in ——— is released as kinetic energy. Some of this kinetic energy heats up graphite which then heats up a fluid (like water). This creates steam and rotates a turbine, which turns a generator.
atoms’ nuclei
In a nuclear reactor, the nuclear energy stored in atoms’ nuclei is released as ———- energy. Some of this kinetic energy heats up graphite which then heats up a fluid (like water). This creates steam and rotates a turbine, which turns a generator.
kinetic
In a nuclear reactor, the nuclear energy stored in atoms’ nuclei is released as kinetic energy. Some of this kinetic energy heats up ———- which then heats up a fluid (like water). This creates steam and rotates a turbine, which turns a generator.
graphite
In a nuclear reactor, the nuclear energy stored in atoms’ nuclei is released as kinetic energy. Some of this kinetic energy heats up graphite which then ————————-. This creates steam and rotates a turbine, which turns a generator.
heats up a fluid (like water)
In a nuclear reactor, the nuclear energy stored in atoms’ nuclei is released as kinetic energy. Some of this kinetic energy heats up graphite which then heats up a fluid (like water). This creates …
steam and rotates a turbine, which turns a generator.
What are the disadvantages of nuclear reactors ?
- Nuclear waste is radioactive and potentially dangerous if not disposed of properly.
- Nuclear waste has a very long half-life, which will continue to be dangerous for a very long time.
What are the advantages of nuclear reactors ?
- No greenhouse gas emission, so no contribution to global warming.
- Reliable, on-demand electricity.
What are the advantages of solar energy generator?
- Renewable.
- Produces no greenhouse gases.
- Produces no noise pollution.
What are the disadvantages of solar energy generator?
- Only produces electricity when there is sunlight.
- High cost of installation.
- Solar cells are currently not very efficient at converting sunlight into energy.
The electromagnetic waves emitted by the ———-, transfer energy to the earth. Solar cells absorb these waves and create an electric current without a generator. Some solar cells use heat from the sun to boil water, create steam and rotate a turbine, which turns a generator.
sun (e.g light)
The electromagnetic waves emitted by the sun (e.g light), transfer energy to the earth. Solar cells absorb these ——- and create an electric current without a generator. Some solar cells use heat from the sun to boil water, create steam and rotate a turbine, which turns a generator.
waves
The electromagnetic waves emitted by the sun (e.g light), transfer energy to the earth. Solar cells absorb these waves and create ——————- without a generator. Some solar cells use heat from the sun to boil water, create steam and rotate a turbine, which turns a generator.
an electric current
The electromagnetic waves emitted by the sun (e.g light), transfer energy to the earth. Solar cells absorb these waves and create an electric current without a ————. Some solar cells use heat from the sun to boil water, create steam and rotate a turbine, which turns a generator.
generator
The electromagnetic waves emitted by the sun (e.g light), transfer energy to the earth. Solar cells absorb these waves and create an electric current without a generator. Some solar cells use heat from the sun to …
boil water, create steam and rotate a turbine, which turns a generator.
What would never be used in a solar power process?
Control rod
Hydroelectric power is produced by …
dams
Solar power comes directly from the …
Sun
Fossil fuels are made of …
decayed plants and animals, which originally got their energy from the Sun.
Water builds up behind the dam due to 1. , which is produced by the 2. , which is driven by the 3.
- rain
- water cycle
- Sun or pumped up using electricity from other sources.
Waves are created by 1. , which are created by …
- winds
- the Sun
Winds are created by …
differences in air pressure
Differences in air pressure arise because of …
air being unevenly heated by the Sun.
What is the origin of the energy stored in fossil fuels?
The sun
The ———————- waves emitted by the sun transfer energy to the Earth.
electromagnetic
All non-renewable resources damage …
our environment
Energy resources can be …
renewable or non-renewable
——————————- (7) are renewable energy resources.
Solar, wind, water waves, hydro-electricity, bio-fuel, tides, geothermal
Renewable resources will never run out. They …
can be or are being replenished as they are used.
Most resources damage the environment. But …
renewable sources are less harmful than non-renewable sources.
—————- are two of the main uses of energy resources.
Heating and transport
Transport is both …
Renewable and Non-renewable
Petrol and diesel vehicles use fuel from ————.
oil
Some steam trains use ———- for boiling water to produce steam.
coal
Bio-fuels power some vehicles.This is …
renewable
————- power some vehicles.This is renewable.
Bio-fuels
Non-renewable heating sources include:
- Natural gas is used to heat homes.
- Coal is burnt in fireplaces.
Renewable heating sources include:
- Some buildings are heated by geothermal heat pumps.
- These use geothermal energy resources.
- Solar water heaters use energy from the sun to heat water.
During which century did electricity use in the UK increase?
20th
During which century did electricity use in the UK decrease?
21st
The way we use energy resources has changed over time because of:
- Changing costs
- Environmental concerns
- Technological advances
For which purpose is geothermal energy used most often?
Heating
Governments are introducing targets for ———— source use because of public pressure.
renewable energy
Governments are introducing targets for renewable energy source use because of …
public pressure.
Renewable energy resources have their limits. These include:
- Politics
- Cost
- Reliability
In terms of cost, renewable energy tends to be ——- expensive than non-renewable energy.
more
Three problems with renewable energy:
- more expensive
- less reliable
- politics can interfere
Which two energy stores are added together to calculate the object’s internal store?
- potential (chemical) store
- kinetic store
Explain why sound travels quickest through solids.
Sound passes through objects by vibrating particles. Sound will travel fastest through solids because the particles are closer together than liquids and gas.
