TOPIC 1: Energy Flashcards
Stores of energy:
- Kinetic store (an object’s movement)
- Gravitational potential store (object’s raised above Earth’s surface)
- Chemical store (chemical bonds between atoms)
- Elastic potential store (when an object is being stretched, compressed or squashed)
- Nuclear store (in the nucleus of an atom)
- Internal store (sum of kinetic energy and potential energy)
What is internal energy?
- The energy stored by the particles that make up an object
- The sum of the kinetic energy and potential energy
How does your body store energy?
- energy is added to your chemical store when you eat food
- it is stored until you need it (your body transfers it to your thermal store when you need to keep warm and kinetic store to move)
kinetic energy equation =
1/2 x m x (v)2
What is the conservation of energy?
Energy cannot be created or destroyed. It can only be transferred from one store of energy into another.
Energy can be transferred by:
- heating
- mechanical work
- waves
- electrical work
Work done equation =
force x distance
What is work done equal to?
The energy transferred to an object
energy equation =
potential difference x current x time
Power equation =
work done/time taken
What is wasted energy?
When one store of energy is transferred to another, some energy is wasted and lost to the surroundings
efficiency of energy transfer equation =
useful energy output/total energy output x 100
How does thermal insulation reduce energy wasted?
- heat would be lost through the roof, windows, walls and floor
- roof = loft insulation
- windows = double glazing
- walls = wall insulation
- floor = carpets
How do lubricants reduce energy wasted
- ## lubrication reduces frictional forces (which allow energy to be dissipated)
What is power?
The rate of energy transfer to a component. It is equal to the rate at which work is done.
In most cases, how does an energy resource generate electricity?
1) rotates a turbine
2) This rotates a coil of wile in a magnetic field, known as a generator
3) In the generator, an electric current can carry the energy to homes and is distributed across the National Grid
What is the advantages of fossil fuels?
Reliable, on demand electricity
What are the disadvantages of fossil fuels?
- non-renewable
- inefficient
- contributes to global warming
What are the advantages of Geothermal energy?
- renewable
- reliable
What are the disadvantages of Geothermal energy
- can only be used where there is volcanic activity close to the surface (magma has lots of internal energy, which heats rocks, which heat water in pipes, which rotates a turbine and turns a generator)
Energy resources:
- geothermal
- solar
- nuclear
- tidal
- water/hydroelectric
- wind
- fossil fuels
What are the advantages of windpower energy?
Source of renewable energy
What are the disadvantages of windpower energy?
unreliable, only produces power when wind blows
