Topic 1 Energy Flashcards
Key Terms/Key Knowledge (41 cards)
Define Closed System
A system that experiences no net change in its total energy when energy transfers occur within it.
Define Conservation of Energy
The law that energy can be transferred, stored or dissipated but never created or destroyed.
Define Efficiency
The ratio of useful output energy transfer to total energy input.
Define Elastic Potential Energy
The store of energy that stretched or compressed objects experience. It is directly proportional to the stiffness constant and to the square of the extension or compression.
Define Fossil Fuels
Coal, oil and gas.
Define Gravitational Potential Energy
The store of energy that all raised matter has. It is directly proportional to the mass of the object, the distance that it is risen and the gravitational field strength at that point.
Define Joule
The unit used for energy. Equal to the work done when a force of one Newton acts over a distance of one metre.
Define Kinetic Energy
The store of energy that all moving matter has. It is directly proportional to the object’s mass and to the square of its velocity.
Define Power
The rate at which energy is transferred, or at which work is done.
Define Renewable Energy Resource
An energy resource that can be replenished whilst it is being used.
Define Specific Heat Capacity
The amount of energy required to raise the temperature of 1kg of a substance by 1°C.
Define Spring Constant
A measure of a spring’s stiffness. The greater the value, the greater the force required to stretch or compress the spring by a given distance.
Define System
A single, or group, of objects.
Define Thermal Conductivity
The higher this value is for a given material, the higher the material’s rate of energy transfer via conduction will be.
Define Waste Energy
Energy that isn’t usefully used for the purpose of the system.
Define Watt
A unit of power. One Watt is equivalent to one joule of work being done in one second.
Define Work Done
The energy transferred when a force acts over a distance.
List the 8 energy stores
Chemical, kinetic, gravitational, elastic, magnetic, electrostatic, thermal, nuclear.
What is unit for work done and energy?
Joule (J)
What term is used to describe energy becoming spread out or transferred to a “wasted” store?
Dissipation
What is the law of conservation of energy?
Energy cannot be created and destroyed but only transferred from one store to another.
What is the equation linking work done, force and distance?
work done = force x distance (W = fs)
What is the unit of force?
Newtons (N)
What is the equation linking gravitational field strength, gravitational potential energy and height?
Gravitational potential energy = mass x gravity x height (EGP=mgh)
