P1 - Conservation and Dissipation of Energy Flashcards
What is conservation of energy?
energy cannot be created or destroyed
What is dissipated energy?
the energy that is not usefully transferred and stored in less useful ways
What is efficiency?
useful energy transferred by a device / total energy supplied to the device
What is elastic potential energy?
energy stored in an elastic object as a result of it being deformed. For example, a stretched spring
What is Hooke’s law?
the extension of a spring is directly proportional to the force applied, as long as its limit of proportionality is not exceeded
What is input energy?
energy supplied to a device
What is power?
the energy transformed or transferred per second. The unit of power is the watt (W)
What is spring constant?
force per unit extension of a spring
What is useful energy?
energy transferred to where it is wanted in the way that is wanted
What is wasted energy?
energy that is not usefully transferred
What is work?
the energy transferred by a force. Work done (joules, J) = force (newtons, N) x distance moved in the direction of the force (metres, m)
What are all the 8 energy stores?
°Kinetic °Thermal °Chemical °Nuclear °Gravitational Potential °Elastic Potential °Magnetic °Electrostatic
Where is a kinetic energy store?
In a moving object
Where is a chemical energy store?
Chemical energy is stored in the bonds that connect atoms with other atoms and molecules with other molecules
Where is a gravitational energy store?
an object above ground
Where is an elastic energy store?
a stretched or squashed object
What is a thermal energy store?
due to a substances temperature
What is a magnetic energy store?
The energy stored when repelling poles have been pushed closer together or when attracting poles have been pulled further apart
What is a nuclear store?
energy stored in the nucleus of an atom
What are all the energy transfer pathways?
- Mechanically,
- Electrically,
- by Heating
- by Radiation
What is mechanical energy transfer?
When a force acts and energy is transferred
What is electrical energy transfer?
When a current flows
What is energy transfer by heating?
Due to temperature difference
What is energy transfer by radiation?
A wave such as light, microwaves or sound