Flashcards
AQA Definitions in Mechanics and Waves - AS Physics
Cards in this deck (32)
- 1ScalarsScalars are quantities that have a magnitude
- 2VectorsVectors are quantities that have a magnitude and direction
- 3EquilibriumFor an object to be in equilibrium, there must not be any resultant force or moment acting on the object
- 4Elastic CollisionIn an elastic collision momentum and kinetic energy is conserved
- 5Inelastic CollisionIn an inelastic collision momentum is conserved but not kinetic energy
- 6WorkdoneA force can do work on an object or supply energy to it, if a force acts on the object whilst it moves
- 7Principle of MomentsFor an object to be in equilibrium, the sum of the clockwise moments is equal to the sum of the anticlockwise moments taken about any point
- 8Centre of MassThe centre of mass/ gravity of an object is the point through which the entire weight of the object is said to act
- 9Newton's 1st LawAn object will remain at rest or move at a constant velocity in a straight line unless acted on by an external force
- 10Newton's 2nd LawWhen a body is acted on by an external force, it's acceleration is proportional to the force applied F=MA
- 11Newton's 3rd LawEverything has an equal and opposite reaction
- 12Terminal VelocityWhen an object falls to the ground or a car accelerates at it's maximum engine power the acceleration of the object will not remain constant
- 13Elastic LimitThe greatest stress that can be applied to a material without causing permanent deformation
- 14Hooke's LawThe extension is directly proportional to the force applied to it provided the elastic limit is not exceeded
- 15Tensile StressDefined as the force per unit cross sectional area of a stretched wire
- 16Tensile StrainDefined as the extension per unit length for a stretched wire
- 17Young's ModulusYoung's modulus of a material is the ratio of the tensile stress to tensile strain
- 18Mechanical WavesProduced by vibrations in a material medium (Eg. Sound waves, S and P waves)
- 19Electromagnetic wavesThey do not travel through a medium but can travel through a vacuum. They travel through space at the speed of light (Eg. Radio, Infrared, UV)
- 20Transverse WavesOscillate at a right angle to the direction of the wave (Eg. EM waves)
- 21Longitudinal WaveOscillate parallel to the direction of the wave (Eg. mechanical)
- 22When light enters an optically denser medium it refracts..Towards the normal
- 23When light enters an optically less dense medium it refracts..Away from the normal
- 24Conditions for TOTAL INTERNAL REFLECTION:*The angle of incidence must be greater than the critical angle
*Light must travel from an optically dense medium to a less optically dense medium - 25Cladding*prevents information to cross over from one fibre making it secure
*Slightly lower refractive index compared to core making it totally internally reflect - 26Optical Fibres (ADVANTAGE)*More information
*More secure
*Little energy lost (Copper loses energy through heat loss) - 27Optical Fibres (DISADVANTAGE)*Impurity
*Modal dispersion
*Spectral dispersion - 28Stationary WavesProduced when two waves of the same frequency, amplitude and constant phase difference travel in opposite directions through the same medium
- 29Coherent SourcesSources which have the same wavelength, frequency, and have a constant phase difference between them
- 30Monochromatic LightIt's light of one wavelength or frequency
- 31Path differenceThe difference in distance travelled by one wave compared to the other
- 32DiffractionIt's the spreading out of waves when they pass through an opening around an obstacle which is comparable in size to their wavelength
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- Definitions in mechanics and waves topic
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- Joven Alimambo
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