Physics Energy Paper 1 Flashcards
What is kinetic energy
Energy in a moving object
What is an energy system
A group of components that work together to produce, store and transfer energy
What happens to energy that can’t be created or destroyed
The energy from one store is carried along a pathway to another energy store
What is chemical energy
Energy stored in chemical bonds
Give an example of chemical energy
Food, fuel, electric batteries
Where is gravitational potential energy found
In objects raised above the earths surface
What is gravitational potential energy
Energy possessed by an object due to its change in position in a gravitational field
What is elastic potential energy
Energy stored due to applying force to deform an object
Where is elastic potential energy found
In stretched, compressed or twisted objects
What is thermal energy
Energy contained within a system that is responsible for its temperature
Where can you find thermal(internal) energy
In any heated object
What is magnetic energy
Energy created by the strength of a magnetic field
Where can you find magnetic energy
In any object with a magnetic field
Define a magnetic field
The area around a magnet where another magnet feels a force
What is electrostatic energy
The potential energy of a system of seperated electric charges
What is nuclear energy
Energy released from the nucleus of an atom
Name four force pathways
Mechanical, electrical, heating, radiation
How do you know if an object has elastic energy
Can return to their original shape and dimension
Why does thermal energy store in a system change
If it’s temperature changes
Define specific heat capacity
The amount of energy needed to raise the temperature of 1kg of a substance by one degree
Define power
The rate at which energy is transferred
A stone and bowl of water are left out in the sun. Which one gets the hottest
The stone feels hotter because it has a lower heat capacity than the water so it doesn’t need as much energy to raise its temperature
What are the units for power
Watts
How does a blowtorch work, what is useful and wasted
Chemical energy transferred into thermal energy which is useful and light energy is wasted
What is an energy store
Is the way that energy is stored in or by objects
What is an energy pathway
The way energy is transferred from one store to another
When is work done
Work is done when a force makes an object or charge move
What does the delta symbol show
change in
How many kg are in 100g
0.1 kg
What is the formula for kinetic energy
Ek= 0.5 x m x v^
mass x speed
What is the formula for gravitational potential energy
Ep = m x g x h
mass x gravitational field strength x height in meters
What is efficiency
How well something works
What is the independent variable
Something I change deliberately
What is the resolution
The smallest measurement you can make using the equipment
What is a parallax error
Viewing angle affects results
What is the formula for force applied
F = k x e
spring constant x extension
Name ways energy moves around
Energy can be stored, transferred or dissipated
What does dissipated mean
Wasted energy
What is unwanted energy
Energy stores that aren’t useful
What happens if a material has high thermal conductivity
The quicker heat is transferred through the material
Name materials that have high thermal conductivity
Brick, concrete, wood and glass
What materials are best for insulation
Materials with low thermal conductivity
What is a closed system
A natural physical system that doesn’t allow transfer of matter in or out of the system except the transfer of energy
What is thermal conductivity
The measure of a materials ability to transfer thermal energy
Why can’t energy be created or destroyed
Total energy supplied to something must always equal to the total energy transferred by something as energy can’t be destroyed or created
Why does trapped air reduce the rate of heat loss
The air has very low thermal conductivity and thermal energy can’t pass through it easily
What is renewable energy
Energy source that can be replenished as it is used
Why are fossil fuels more reliable
They produce a constant energy supply with no gaps in delivering energy
Why is storing nuclear waste dangerous
Radioactive causing cells to mutate and radioactivity lasts for thousands of years
What is biofuel
Made from plant matter
How is energy created by wind
The turbines spin a generator to produce electric
How does hydroelectric energy work
Falling water spins a turbine to produce electricity
How is geothermal energy created
Hot rocks underground produce steam
How do tides create energy
The rise and fall of the tide is used to turn a turbine
How do waves create energy
The up and down movement of the waves turns turbines
How does the sun create energy
Energy from the sun is converted into power
What formula combines distance, work done and force
Work done= force x distance
What is the formula for change in thermal energy
Change in thermal energy = mass x specific heat capacity x temperature change
What is the formula for efficiency
Efficiency = useful energy output ÷ total energy input
Efficiency = useful power output ÷ total power input
What is the formula for power
Power = work done ÷ time taken
Power= energy transferred ÷ time taken
Why does a bungee jumper slow down once thr cord begins to stretch
Kinetic energy decreases as its converted into elastic potential energy and kinetic energy is proportional to velocity so ad ke decreases do does velocity
What is the law of conservation
Energy can’t be created or destroyed
When a ball is kicked state any changes in the total energy of the ball
The total energy remains constant due to the conservation of energy
How can efficiency of a system be increased
Reducing waste output by lubrication (also reduces friction in moving parts) or thermal insulation
Recycling waste output by recycling thermal waste energy as input energy
How can efficiency of a radiator be improved
Install metal foil sheets behind the radiator to reflect heat back into the room
What are two disadvantages of using renewable energy
Output determined by external factors such ad wind speed so supply is uncertain
Generating it through other means is often more efficient and cheaper
What are some disadvantages of using biofuels
When plants are burned they produce CO2, need to destroy land to grow biofules, growing biofuels reduces land available for growing food
