6.1.2.1 - Energy Transfers in a System Flashcards
(Content Continued in ‘P2 – Energy Transfer by Conduction’ Notes)
What can energy do and can’t do?
Energy can be transferred usefully, it can be stored and dissipated, butW cannot be created or destroyed.
What happens when there is an energy transfer in a system?
Energy is transferred, and also some energy is dissipated.
What is the Conservation of Energy Law?
It is the concept that energy cannot be created or destroyed, and can only be transferred
usefully, stored or dissipated.
What does the concept that energy cannot be created or destroyed, and can only be transferred
usefully, stored or dissipated (the Conservation of Energy Law) means?
This means that despite a change in energy store, the net total amount of energy overall will remain the exact same
once the energy transfer has completed.
What is dissipation?
It is the spreading out and transfer of energy stores into less useful/unwanted forms. It is often referred to
as ‘wasted energy’, because it is not transferred to a wanted output.
What happens to energy during near all energy transfers?
Near all energy transfers will have some dissipation, where some ‘wasted energy’ is transferred to its surroundings.
Give an example of energy dissipation in electrical systems.
Electrical cabling can dissipate some of the electrical energy into the surroundings as thermal energy.
How is energy dissipated in a mechanical system?
Energy will be dissipated when two surfaces rub together because work done against the
friction of the system will create unwanted/wasted thermal energy, increasing the internal (thermal) energy.
What role does lubricant play in mechanical systems?
The use of lubricant between surfaces reduces friction in mechanical systems, which reduces ‘wasted energy’ transfers.
