P1. Conservation And Dissipation Of Energy Flashcards
Which ways can energy be stored?
- chemical ~ fuels, food
- kinetic ~ moving
- gravitational potential ~ position to ground
- elastic ~ stretched or squashed
- thermal ~ temperature
How can energy be transferred?
By heating, waves, electric current or when a force moves an object
What is a closed system?
Isolated system in which no energy transfers take place out or into the energy stores of the system
What is work done?
When a force makes an object move
What happens to the gravitational field strength of of an object when it is moved?
When moved up it increases (because work is done to overcome the gravitational force)
When moved down it decreases
What does wasted energy transfer to?
The surroundings which make it warmer
What does energy dissipating mean?
Energy spreads out which makes it less and less useful
How do machines waste energy?
Friction between moving parts, air resistance, electrical resistance and noise
How can machines be made more efficient?
- lubricant to reduce friction
- shape to make it more air resistant
- copper wire to minimise electrical resistance
What is the principle of conservation of energy?
Energy cannot be created or destroyed
Describe the transfer of energy in a pendulum
As it swings to the middle the gpe decreases and kinetic energy increase.
As it moves away from middle he kinetic energy decreases and gpe increases
What is the gfs on the surface of the earth and moon?
Earth is 9.8N/kg and the moon is about a sixth of the earths value
What does the energy in the kinetic energy store of depend on?
Mass and speed
What isn’t elastic potential energy?
Energy stored in an elastic object that has been stretched or squashed
Why can energy be ‘wasted’ but not ‘lost’?
Energy cannot be created or destroyed, but is wasted when its not usefully transferred
