PHYSICS Flashcards
(30 cards)
Define energy.
Energy is the capacity to do work. It represents the ability of something to perform.
How many energy stores are there? Name them.
There are eight energy stores:
- Kinetic
- Gravitational Potential
- Thermal
- Nuclear
- Elastic potential
- Electrostatic
- Magnetic
- Chemical
What is energy transfer? Name the four inputs.
Energy transfer is the act of energy moving from one system or location to another. The four inputs are:
- Mechanical work
- Electromagnetic radiation
- Electric work
- Heating
Define ‘conduction’
Conduction is the transfer of energy, such as heat or an electrical charge, through a substance.
Define ‘current’
A current is the flow of electricity in an electronic circuit, and the amount of electricity flowing through a circuit.
Define ‘convection’
Convection is a heat transfer that only occurs in liquids and gases, due to it involving the substances to physically move.
Define ‘kinetic energy’. Name a system that may create kinetic energy. Give the formula for kinetic energy.
Kinetic energy is the energy that an object possesses due to its motion. The faster an object moves, the more kinetic energy it has.
A car produces kinetic energy as it drives.
The formula for kinetic energy is:
KE = 0.5 X mass X (velocity X velocity).
Define ‘chemical energy’. Give an example of a system that may use or produce chemical energy.
Chemical energy is a form of potential energy that is stored in the bonds of chemical compounds, such as atoms and molecules. The food we eat contains chemical energy that our bodies convert into usable energy through metabolism.
Define ‘electrostatic energy’. State the formula for the energy. Give an example of electrostatic energy.
Electrostatic energy is the potential energy stored in a system of charged particles due to their positions relative to each other. The formula for electrostatic energy is:
U = k q1 q2 / r
Electrostatic energy is commonly used in capacitors.
Define ‘elastic potential energy’. Give an example of elastic potential energy. State the formula.
Elastic potential energy is stored in an object when it is deformed, such as when it is stretched or compressed. Some examples of systems that use elastic potential energy are springs and rubber bands. The formula is:
EPE = ½ kx^2
Define ‘gravitational potential energy’. Give the formula and an example of a system that may use or produce the energy.
Gravitational potential energy (GPE) is the energy stored in an object as a result of its position in a gravitational field. A book resting on a shelf has gravitational potential energy due to its height above the ground. The formula is:
GPE = mgh.
Define ‘magnetic energy’. Give the formula.
Magnetic energy refers to the energy stored in a magnetic field, which is generated by electric currents or the alignment of magnetic materials. The formula is:
U = ½ x L x I^2
Define ‘thermal energy’. Give examples of systems that may use it.
Thermal energy is the total kinetic energy of the particles in an object or substance. Some examples include:
- Heating systems.
- Cooking systems.
Define ‘nuclear energy’. Give advantages, disadvantages.
Nuclear energy is a powerful source of energy that comes from the nucleus of atoms.
Advantages:
- High energy density
- Low greenhouse gas emissions
Disadvantages:
- Radioactive waste
- High initial costs
What is the Law of Conservation of Energy?
Energy cannot be created nor destroyed, rather transferred from one system to another
Name the energy store related to moving?
Kinetic energy.
How is most energy wasted?
Irresponsible human behaviour and inefficient systems
Friction is a _________?
Friction is a contact force.
Work done is _______?
Work done is the amount of energy transferred.
How do you calculate work done?
Work Done (J) = Force (N) x Displacement (m).
What is the energy store related to heat?
Thermal energy.
What is energy measured in?
Energy is measure in Joules (J)
What is force measured in?
Force is measured in Newtons (N)
What is displacement measured in?
Displacement is measured i meters (m)
