P1-conservation and dissipation of energy Flashcards
What are the eight energy stores?
Thermal energy store Kinetic energy store Gravitational potential energy store Elastic potential energy store Chemical energy store Magnetic energy store Electrostatic energy store Nuclear energy store
What are the different ways energy can be transferred?
- Mechanically(by a force doing a work)
- Electrically(work done by moving charges)
- Heating
- Radiation(e.g light or sound)
What is a system?
A system is a single object or a group of objects that you are interested in
What happens when a system changes?
When a system changes, energy is transferred. It can be into or away from the system, between different objects in the system or between different types of energy stores(e.g from the kinetic store of an object to its thermal energy store)
What is a closed system?
A closed system are systems where neither matter nor energy can enter or leave. The net change in the total energy of a closed system is always zero.
How is energy transferred be heating e.g from boiling water in a kettle?
Think of the water as the system. Energy is transferred to the water by heating, into the water’s thermal energy store causing the temperature of the water to rise.
What energy stores does it go through when an object falls and hits the ground.
First it has a lot of gravitational potential energy but as the object is falling it speeds up which transfers the energy into the kinetic energy store and when it hits the ground the energy is transferred to the surroundings.
What are chemical energy stores?
Fuels, foods or the chemicals found in batteries. The energy is transferred during chemical reactions.
What is kinetic energy store?
Kinetic energy stores describe the energy an object has because it is moving.
What is gravitational energy store?
Gravitational potential energy stores are used to describe the energy stored in an object because of its position, such as an object above the ground.
What is elastic potential energy store?
Elastic potential energy store describes the energy stored in a springy subject when you stretch it or squash it.
What is thermal energy store?
Thermal energy store describes the energy a substance has because of its temperature.
What is conservation of energy principle?
Energy can be transferred usefully, stored or dissipated but can never be created or destroyed.
When energy is transferred is all of it used in a useful way?
No, not all the energy is transferred usefully into the store that you want it to go in. Some energy is always dissipated when an energy transfer takes place.
What is dissipated energy?
It is wasted energy because the energy is being stored in a way that is not useful.
What is work done?
The energy transferred when a force acts over a distance
What does it mean work is done on an object?
Work is done on an object when a force makes the object move