1. Energy (energy stores and energy pathways) Flashcards
How is energy transferred?
It is transferred between stores
What happens when energy is transferred to an object?
The energy is stored in one of the object’s energy stores
What are the 8 energy stores?
- Thermal energy stores
- Kinetic energy stores
- Gravitational potential energy stores
- Elastic potential energy stores
- Chemical energy stores
- Magnetic energy stores
- Electrostatic energy stores
- Nuclear energy stores
What are the 4 energy pathways (ways energy can be transferred through stores)?
- Mechanically
- Electrically
- By heating
- By Radiation
What does energy transferred mechanically mean?
Energy is transferred by a force doing work
What does energy transferred electrically mean?
It is energy transferred by moving charges
What is kinetic energy?
Energy that moving objects have in their kinetic store
What is gravitational potential energy?
Energy that is gained by an object when it is lifted above the ground
What is elastic potential energy?
Energy that objects store when an object is stretched
What is electrostatic energy?
Energy that is stored from charged objects interacting with one another
What is magnetic energy?
Energy stored from magnets interacting with each other
What is nuclear energy?
Energy stored from the energy released by atomic nuclei during nuclear reactions
What is thermal energy?
Energy stored by the temperature of the object (the hotter the object, the more thermal energy it has in this store)
What is chemical energy?
Energy stored from the energy that is released during chemical reactions
What is the gravitational field strength of earth?
9.8 n/kg
What is a system?
An object or group of objects
What happens when a system changes?
When a system is changed, the way energy is stored also changes
What happens when a system is in equilibrium?
Nothing changes, and so nothing happens, so no energy is transferred
What are closed systems?
Systems where neither matter nor energy can enter or leave
What is the net change in the total energy of a closed system?
0
What are the 3 things a system can be?
Open, closed or isolated
Describe the energy changes involved when a ball is thrown upwards and then returns to its starting position. Ignore air resistance
- Upwards: KE is converted to GPE
- Peak: maximum GPE, zero KE
- Downwards: GPE is converted to KE
Explain why a bungee jumper slows down as the cord begins to stretch
- Kinetic energy decreases since its converted to elastic potential energy
- Since KE is proportional to velocity squared, as KE decreases, so does velocity
