Energy Flashcards
What is kinetic energy?
The energy stored by an object’s movement
What is Elastic energy?
The energy stored when an object is being stretched or squashed
What is gravitational potential energy?
Why does it exist?
- The energy stored in objects raised above the Earth’s surface
- This energy exists because of the Earth’s gravitational field
What is internal energy?
The sum of the kinetic and chemical energy of the particles that make up an objects
What is nuclear energy?
The energy stored in the nucleus of an atom
What is chemical energy?
The energy stored by chemical bonds between atoms
What is the equation for G.P.E?
GPE (J) = Mass (Kg) x GFS (N/Kg) x Height (M)
What type of energy do you gain when you eat food?
Chemical
Name some examples of energy conversion…
- Bringing water to a boil in an electric kettle
- An object accelerated by a constant force
- A vehicle slowing down
- An object projected upwards
- A moving object hitting an obstacle
What can never happen to energy?
- Be created
- Be destroyed
Name the 6 key types of energy…
- Chemical
- Elastic potential
- Nuclear
- Internal
- Kinetic
- Gravitational potential
Where does chemical energy come from?
Comes from the potential energy stored in the bonds between particles
Where does kinetic energy come from?
- Comes from the random motion of the particles
- The temp of a body (object) is a measure of the kinetic energy of its particles
- Increasing a body’s temp increases the kinetic energy of the body’s particles, increase in the body’s internal energy
What two types of energy are internal?
- Kinetic
- Chemical
What is Gravitation potential energy measure in?
Joules (J)
Which of these has the larger kinetic energy assuming they are traveling at the same velocity?
Mouse or Elephant
Cat or Rhinoceros
Guinea pig or Dog
Elephant
Rhinoceros
Dog
If the mass of an object is 2kg, the gravitational field strength is 4 and the change in height is 2m, what is the change in GPE (gravitational potential energy)?
16 J
Where does the chemical energy that contributes to internal energy come from?
The potential energy stored in the bonds between particles
Name 4 method of energy conversion…
- Heating
- Electrical work
- Mechanical work
- Waves
What does heating increase?
An objects internal energy (Which is the sum of the kinetic and chemical energy of its particles)
What is electrical work?
When an electrical current transfers energy from one object to another
What is mechanical energy?
When energy is transferred from one object to another via a force
What are waves?
Structures that can transfer energy from one object to another e.g. Light and sound
Which principle tells us that energy cannot be created or destroyed?
Conservation of energy
What is the equation for work done?
Work done = force x distance (moved along the line of action of the force)
More work is done if you:
- push with the same force for a longer distance
- or push with a larger force for the same distance
The work done by a force is equal to…
the energy transferred to the object.
A book is pushed 10cm along a desk by applying a force of 8N. What is the work done on the book?
- Remember the equation for work done
W = F × d - Convert to correct units
10 cm = 0.1 m - Substitute the values in.
W = 8 N × 0.1 m - Calculate work done
W = 0.8 J
Which of these quantities is considered in the equation for work done?
- Speed
- Force
- Time
- Mass
Force
What is the electrical energy transferred to a component with a power rating of 10W is switched on for 4s?
- Remember the equation for electrical energy
E = P t - Substitute the values in
E = 10 × 4 - Answer
E = 40 J
What Is the equation for electrical work - Work done when a current
E=VIt
Energy = Potential difference x current x time
What is the charge for electrical current?
energy=charge×potential difference
A book is pushed 60cm along a desk by applying a force of 12N. What is the work done on the book?
- Remember the equation for work done
W = F × d - Convert to correct units
60 cm = 0.6 m - Substitute the values in.
W = 12 N × 0.6 m - Calculate work done to appropriate number of significant figures
W = 7.2 J
What is the electrical energy transferred to an component when a charge of 3C passes through a potential difference of 2V?
- Remember the equation for electrical energy
E = Q V - Substitute the values in.
E = 3 × 2 - Answer
E = 6 J
What is the equation for power?
Power (W) = work done (J) divided by Time (S)
- Power is the rate of energy transfer (or work done).
Power is the rate of…
Energy transfer
What is power?
- Power is the rate of energy transfer (or work done). The faster that energy is transferred (or work is done), the higher the power.
- Power (P) is the rate of energy transfer to a component. This is the same as saying power is the energy transferred per second. It is also equal to the rate at which work is done.
The ………. done by a force is equal to the ……….. transferred to the object.
- work
- energy
The faster that energy is transferred (or the faster work is done), the …………. the power.
- higher
When one type of energy is converted into another type of energy, some energy is …………….. (transferred into unwanted types of energy).
- wasted
what is the equation for the Efficiency of an energy transfer?
efficiency of energy transfer (%) = useful energy output (J) divided by total energy input (J) ×100
How is efficiency most often expressed?
As a percentage
Name 4 types of thermal insulation and why they are used…
- Loft insulation (The roof)
- Double glazing (Windows)
- Cavity walls insulation (Walls)
- Carpets (Floors)
because heat is lost through these places
how can we decrease the rate a house cools at?
- Having thicker walls
- Having walls made from a material with low thermal conductivity
- 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
What does lubrication decrease?
Frictional forces
What state are lubricants usually found in?
Liquid
The higher the ……….. conductivity of a material the higher the rate of energy transfer by conduction across the material.
thermal
How can we reduce unwanted energy transfer?
Thermal insulation and lubrication
What are the equations for power?
Power (W) = Work Done (J) / Time (S)
Power (W) = Energy Transferred (J) / Time (S)
When a current flows through a light bulb, it emits 30 J light energy in 2 seconds, what is the power of the bulb?
15 W
what is wasted energy?
Energy that is not used for its intended purpose - such as heat energy in a wire.
what does friction create?
Creates heat energy in almost every energy transfer which is then dissipated.
what is dissipation?
When energy spreads out to anything nearby.
Efficiency can never be greater than …….%.
100%
Lubrication reduces …………… forces.
frictional
A speaker, receives 20J of energy over a period of 5 seconds. What is the power?
- Remember the equation for power
P = E ÷ t - Substitute the values in
P = 20 ÷ 5 - Write the answer, remembering to include the appropriate unit
P = 4 W
In most cases, to generate electricity, an energy resource rotates a ………………….
turbine
How is energy obtained from fossil fuels?
Fossil fuels (such as coal and oil) are burnt, to heat a fluid (water), which creates steam and turns a turbine (creating kinetic energy). The turbine rotates, which turns a generator.
Name 3 disadvantages of fossil fuels…
- Not renewable
- Inefficient
- Contributes to global warming
Name an advantage of fossil fuels…
Reliable, on time energy
What is a disadvantage of geothermal energy?
-Can only be used when there is volcanic activity close to the surface
Name 2 advantages of geothermal energy…
- Renewable
- Reliabe
how is geothermal energy obtained?
In volcanic places, magma (underground lava) has lots of internal energy. The magma heats rocks, which heat water in pipes. This rotates a turbine, which turns a generator
Name 7 energy resources….
- Geothermal
- Solar
- Nuclear
- Tidal
- Water/Hydroelectric
- Wind
- Fossil fuels
Which types of energy are usually involved in an electrical generator?
- Kinetic
- Electrical
Some examples of fossil fuels are:
- Oil
- Coal
- Natural gas
In volcanic places, ……………… (underground lava) has lots of internal energy
magma
how is energy obtained from wind?
Wind is a natural source of kinetic energy. Wind blows and the turbine rotates, which turns a generator.
what is a disadvantage of wind power?
unreliable, only produces energy when wind is present
what is an advantage of wind power?
- source of renewable energy
- no fuel costs
how is enegy obtained from water?
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.
name 2 advantages of Water (Hydroelectric Power)?
- Renewable
- More reliable than wind and solar
name a disadvantage of Water (Hydroelectric Power)…
Hydroelectric dams often change the paths of rivers, which can move people out of houses and harm local wildlife
how is energy obtained by wave and tides?
The waves and tides in the sea are stores of kinetic energy. Tidal and wave power use this kinetic energy to rotate a turbine, which turns a generator
What is a disadvantage of tidal power?
The creation of tidal turbines can damage fragile ecosystems in estuaries
Name an advantage of tidal power…
renewable source of energy
The waves and tides in the sea are stores of ………… energy.
kinetic
Wind is a natural source of …………. energy.
kinetic
One disadvantage of hydroelectric power is that the electricity used to pump water may have come from ………………… fuel sources.
fossil
how is energy obtained from nuclear?
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
name 2 advantages of nuclear energy…
- no gas emissions so no contribution to global warming
- reliable, on demand energy
name an advantage of nuclear energy…
-disposal of nuclear waste with very long half-life
In the production of nuclear power, some of the kinetic energy released from atoms’ nuclei heats up …………. , which then heats up a fluid such as water.
graphite
how is energy obtained from solar energy?
The electromagnetic waves emitted by the sun (e.g light), transfer energy to the earth. Solar cells absorb these waves and create electrical energy without a generator. Some solar cells use heat from the sun to boil water, create steam and rotate a turbine, which turns a generator.
hat is a disadvantage of solar energy?
only produces energy wen there is sunlight
name an advantage of solar energy…
renewable
One of the main advantages of solar power is that it will never run out - it is a ……………………….. source of energy.
renewable
What is the riginal ource of energy?
the sun
What are fossil fuels made of?
decayed plants and animals which have originally got their energy from the sun
where does solar power directly come from?
the sun
how are winds created?
by differences in air pressure- these differences in air pressure arise because of air being unevenly heated from the SUN
how are waves created?
by winds which are created by the SUN
how is sun an energy source from hydroelectric power produced in dams?
- hydroelectric power is produced in dams.
- Water builds up behind the dam due to rain, which is produced by the water cycle, which is driven by the sun or pumped up using electricity from other sources
Fossil fuels are made of decayed …………. and animals, which originally got their energy from the Sun.
plants
The Sun is the original source of energy for the following forms of power…
- hydroelectricity
- fossil fuels
………………. and ……………….. are two of the main uses of energy resources.
- heating
- transport
Since the beginning of the 21st century, electricity use has been ………………….. in the UK.
decreasing
larger populations = ………….. use of electricity
larger
appliances have become more ……………..
efficient
Over the 20th century, electricity use ………………….. in the UK because the population of the UK grew bigger.
increased
name 3 reasons why the use of energy has changed over time…
- Environmental concerns
- Changing costs
- Technological advances
All …………………… resources damage our environment
non-renewable
Solar water heaters use energy from the ……………. to heat water.
sun
What percentage of energy does the UK government plan to draw from renewable resources in 2020?
and why??
15%
- People are becoming more aware of how damaging fossil fuels are to the environment.
Governments are introducing targets for renewable energy source use because of ……………………… pressure.
public
what are 3 limits to Renewable Energy Resources?
- Cost
- Reliability
- Politics
In terms of cost, renewable energy tends to be …………………. expensive than non-renewable energy
more
To help solve the energy problem, energy providers are building power plants that use ……………………. resources.
renewable
