Energy Flashcards
(17 cards)
What is a system
A system is an object or group of objects
A sytem can store ____ via multiple stores. Give examples
energy
Magnetic, kinetic, thermal, gravitational potential, chemical, elastic potential, electrostatic, nuclear
Energy can be _____ between stores
transferred
Conservation of energy in a closed system
In a closed system, energy cannot be created nor destroyed, only transferred
Energy is measured in joules (J)
Gravitational potential energy
Energy gained by raising an object against the action of a gravitational field
Gravitational field strength on earth
9.8n/kg
Kinetic energy
Energy stored by a moving object
Elastic potential energy
Energy stored in a stretched spring or elastic band
Specific heat capacity
Energy needed to raise the temp of 1kg of a substance by 1c
Power
the rate at which energy is transferred or work is done
what is a joule
1 watt per second
Efficiency
The proportion of energy which is usefully transferred
Ways to reduce heat loss
Insulation
Ways to reduce drag
Streamlining
Ways to reduce friction
Use wheels
Lubrication
Frictional forces cause energy to be __________.
by heating
Renewable vs non renewable energy resources
Renewable - a resource that is generated faster than it is used
Non renewable - a resource which is being used faster than it is being generated
