Definitions Flashcards
Centre of mass
The point on the body where the mass is considered to be concentrated from
Centre of gravity
The point on the body where the weight is considered to act
EMF
The amount of energy transferred by a source to each unit of charge that passes through
ohms law
The current and potential difference through an ohmic conductor, held under constant physical conditions are directly proportional (resistance)
Potential divider
A method of splitting a potential difference, by connecting two resistors in series.
Total potential difference of split in the ratio of their resistances.
coherence
waves with the same wavelength, frequency, and they’re being fixed phase difference between them
Material dispersion
waves of different wavelengths travels slightly different speeds through an optical fibre
so reach the end of the fibre at slightly different times, causing pulse broadening
modal dispersion
waves into an optical fibre slightly different angles, meaning the distance each beam has to travel is slightly different
This leads to the beams reaching the end at different times and so causes post broadening.
pulse broadening
The elongation of a signal passed down an optical fibre
commonly due to model or material dispersion
stationary wave
A waved that stores, but does not transfer energy
couple
2 equal and opposite parallel forces act on an object, three different lines of action, causing a rotation .
elastic strain energy
The energy stored in an object when it is stretched
It is equal to the work done to stretch the object
equal to the area under a force extension graph.
equilibrium
Resultant forces on the object equal zero
Hookes law
Extension of an elastic object will be directly proportional to the force, applied to it up to the objects limit of proportionality
impulse
The change of momentum of an object when a force acts on it
Equal to the product of the force acting on the object and duration of time
Newton’s first law
An object will remain in its current state of motion, unless acted on by resultant force
an object requires a resultant force to be able to accelerate
Newton second law
The sum of forces acting upon an object, is equal to the rate of change of momentum of the object
Newton‘s third law
If body A exerts a force on body B, then body B will exert an equal and opposite force on body A
terminal speed
The maximum speed of an object when the resistance and driving forces are equal
Young modulus
The ratio of stress to strain for a given material
Resistance
A measure of how difficult it is for current to flow through a material
Current
Rate of flow of charge
