Physics definitions

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Scalar
A quantity with just magnitude
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Vector
A quantity with magnitude and direction
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Displacement
Distance in a particular direction
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Velocity
The rate of change of displacement
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Acceleration
The rate of change of velocity
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Instantaneous speed
The speed at a given time ( can be seen as the gradient on a distance time graph)
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Average speed
Ratio of distance to time
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Newton
The force required to give a mass of 1kg the acceleration of 1ms^-2
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Terminal velocity
The maximum speed of an object as a result of an equal drag to driving force ( usually the force of gravity)
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Center of gravity
The point through which the weight of an object can be considered to act
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Couple
a pair of equal, parallel forces that produce a rotation
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Torque
One of the forces x the perpendicular distance between the forces
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Moment
Force x perpendicular distance between the force and the pivot/given point
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Thinking distance
The distance a vehicle travels from the instance the driver sees the need to apply the brakes and the instance that the brakes are applied
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Braking DIstance
The distance that the vehicle travels between the instance that the brakes are applied to the instance that the vehicle comes to a complete stop
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Stopping Distance
The sum of the thinking distance and the braking distance
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work done
Force multiplied by the distance in which the force is acting
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Joule
The work done when a force of 1N moves its point of application 1m in the direction of the force
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Conservation of Energy
Energy can not be created or destroyed but may be transferred from one form to another
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Power
The rate of doing work
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Watt
1 joule per second`
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Tensile force
Stretching force; two equal and opposite forces are required to put an object under tension
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Compressive force
Squeezing/Squashing ; two equal and opposite forces acting towards the object.
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Extension
Change in length from the original length
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Elastic limit
The point in which an extended or deformed object will no longer return to its original shape
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Stress
Force per unit Cross sectional area
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Strain
Extension per unit length
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Young's modulus
Ratio of stress to strain ( Stress/Strain)
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Ultimate Tensile Strength
That maximum stress an object can endure before fracture
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Elastic deformation
The deformation of an object which will return to its original shape when the force is removed
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Plastic deformation
The deformation of an object that has resulted in the permanent deformation when the force is removed
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Weight
W = mass x acceleration due to gravity (g)
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Electric current
The net flow of charged particles per unit time through a point
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Conventional current
A model used to describe the movement of charged particles in a circuit
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Electron flow
The movement of electrons around a circuit. Negative to positive
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Electric charge
(C), 1 coulomb being the total charge supplied by a current of 1 ampere in a time of 1 second
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elementary charge
The charge on one electron is 1.6x10^-19
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Kirchoff's 1st law
The sum of the current flowing into a junction is equal to the sum of the current flowing out of the junction as charge is conserved
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Mean drift velocity
The average speed of charged particles along the length of a conductor
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Conductor
A material with a high number density of conduction electrons and therefore a low resistance
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Semi conductor
a material with a low number density of conduction electrons and therefore a high resistance
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Insulator
A material with a number density of conduction electrons nearing 0 and therefore a very high resistance
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Electromotive force (emf)
Energy transferred per unit charge when a type of energy is being converted to electrical energy.
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Potential difference (pd)
Energy transferred per unit charge when electrical energy is converted into another form of energy
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Power
Work done per unit time
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Resistance
Potential difference across a component per unit current
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Ohm's law
the current that flows through a component is directly proportional to the potential difference across it providing physical properties such as temperature remain constant
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Kirchoff's 2nd
The sum of the emfs around a loop is equal to the sum of the pds around the same loop - conservation of charge
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Internal resistance
The resistance of an emf source eg; a cell
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Potential divider circuit
A type of circuit containing two components designed to divide the pd in proportion to the resistances of the components
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Progressive waves
move through a material transferring energy from one position to another
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longitudinal waves
motion of the oscillation of particles is parallel to the direction of the propagation
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Transverse waves
Motion of the oscillations of particles is perpendicular to the direction of the propagation
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Amplitude
Maximum displacement from the point of equilibrium
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Wavelength
The smallest distance between waves - peak to peak / trough to trough
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Period
The time taken to complete one full oscillation ( peak to peak)
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frequency
The number of oscillations passing per second ( f=1/T)
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Phase difference
the proportion of a cycle by which the two waves are "out of sync"
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Wave speed
Speed with which energy is transmitted by a wave v=fλ
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Intensity
Rate of energy transfer per unit area (at right angles to wave velocity)
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Reflection
When waves rebound from a barrier resulting in a change of direction
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Refraction
When waves change direction when they travel from one medium to another due to difference in wave speed in each medium
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Diffraction
When a wave spreads out after passing around and obstacle or through a gap
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Electromagnetic waves
A self-propagating transverse wave that doesnt require a medium to travel through
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Polarity
A wave property that distinguishes between transverse and longitudinal waves
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Plane polarised
A transverse wave that only oscillates in one direction
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Principle of Superposition
the ability for a wave to pass through each other and then continue unaffected
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Interference
The superposition of 2 or more coherent waves resulting a new wave/
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Coherence
two waves with a constant phase relationshop over a significant period of time
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Path difference
The proportion of the wavelength that the 2 waves are 'out of sync'
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Constructive interference
When two waves superimpose to create an increased amplitude
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Destructing interference
When two waves superimpose to create a reduced amplitude
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Stationary waves
A wave pattern produced when two progressive waves of the same frequency travelling in opposite directions superimpose, energy is stored rather than transferred from on place to another
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Antinode
Point of maximum amplitude along a stationary wave
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Node
A point that has 0 amplitude along a stationary wave as a result of destructive interference
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Fundamental mode of vibration
The simplest stationary wave that can be set up where the length of the string is have the wavelength
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Fundamental frequency
Lowest frequency in harmonics series where a stationary wave forms
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harmonics
Whole number multiples of the fundamental frequency of a stationary wave
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Photon
A quantum of energy of EM radiation
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ElectronVolt
The energy change of an electron when it moves through a potential difference of 1 volt
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Work function φ
minimum energy required by a single electron to escape the metal surface
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Threshold frequency
The minimum frequency required to release electrons from the surface of a metal
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De Broglie equation
λ=h/mv - an equation expressing wavelength as a ratio of planck's constant and the particles momentum
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Card 2

Front

A quantity with magnitude and direction

Back

Vector

Card 3

Front

Distance in a particular direction

Back

Preview of the back of card 3

Card 4

Front

The rate of change of displacement

Back

Preview of the back of card 4

Card 5

Front

The rate of change of velocity

Back

Preview of the back of card 5
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