Energy Stores and Transfers Flashcards
What is a system?
An object or group of objects.
When does an object have kinetic energy?
When it is moving
What is a closed system?
A system where no energy can escape to or enter from the surroundings. The total energy does not change.
Why would an object have gravitational potential energy?
Because of its height above the ground
When does an object have elastic potential energy?
When it is stretched or compressed
Why would an object have thermal energy?
Because of its temperature
What is chemical energy?
Energy transferred through chemical reactions (e.g: foods, fuels and the chemicals in batteries)
What is nuclear energy?
Energy stored in the nucleus of an atom
What is magnetic energy?
Energy a magnetic object has when it is near a magnet/in a magnetic field
What is electrostatic energy?
Energy a charged object has when near another charged object
What are the 4 ways of energy transfer?
Mechanical, electrical, radiation, heating
What can energy not be?
Created or destroyed
What is dissipated energy?
Energy “lost” or wasted
What is useful energy?
Energy successfully transferred to the store
When is energy transferred entirely usefully?
Never.
Which energy store of the surroundings is all dissipated energy transferred to?
Thermal store
What is a way of reducing wasted energy transfer due to friction?
Lubrication
What is a way of reducing wasted energy transfer due to air resistance/drag in water?
Streamlining
What is a way of reducing energy wasted due to heat dissipated to the surroundings?
Thermal insulation
What is efficiency?
A measure of how much energy is transferred usefully.
What is the unit for energy?
Joules (J)
What is work done?
Energy transferred when a force moves an object
Describe the energy transfer when a moving car slows down.
Energy is transferred mechanically from the kinetic store to the thermal store of its brakes.
Some energy is dissipated to the thermal store of the surroundings.
What is the unit that represents 1J transferred per second?
Watt
What is 1J of work?
The work done when a force of 1N causes an object to move 1m in the direction of a force.
