Flashcards
A2 Physics Oscillations
Cards in this deck (38)
- 1Free oscillationsA body oscillates at its natural frequency where no external force is applied and no energy is lost
- 2Forced oscillationsContinuous energy is input to a body to make it oscillate by an external driving force
- 3Natural frequencyThe frequency an object vibrates freely after an initial disturbance
- 4AmplitudeThe maximum displacement from the equilibrium position of an oscillation
- 5PeriodThe time taken for one complete oscillation
- 6FrequencyThe amount of oscillations per second
- 7How the displacement time graph of an oscillation looks (where time starts at amplitude)Shape of a cosine graph
- 8PhaseThe point that an oscillating mass has reached within the complete cycle of an oscillation (how far along the cycle it is)
- 9Phase differenceThe difference in the phases of two oscillating particles, expressed in degrees or radians
- 10Simple harmonic motionMotion of an oscillator in which its acceleration is directly proportional to its displacement from its equilibrium position and is directed towards that position
- 11Examples of shmWhen an alternating current flows in a wire (electrons vibrate in shm)
Atoms in a molecule vibrate with shm - 12Requirements for shm in a mechanical systemA mass that oscillates
A position where the mass is in equilibrium
A restoring force that acts to return the mass to its equilibrium position and must be directly proportional the the displacement from the equilibrium position and directed towards that point - 13Changes in velocity, acceleration and displacement in shmSince these are vector quantities, there will be a side to the oscillation that will have negative values
- 14Velocity time graph for shmGraph in the form of negative sine
- 15Acceleration time graph of shmGraph of negative cosine
- 16Equation of displacement/velocity/acceleration for shm
- 17Angular frequencyRelated/Identical to angular velocity
The frequency of a sinusoidal oscillation expressed in radians per second - 18How to calculate angular frequency2 x pi x f
2 x pi / T - 19When to start with sin or cosineWhen calculating displacement - use sine when the timing starts at the equilibrium position and cosine at the amplitude
- 20Equation of shm (general)a = - (angular f)^2 x displacement
- 21Energy changes in shmThere is a constant interchange of energy between two forms: potential and kinetic
- 22At amplitude, state the energyMaximum potential energy
Minimum/zero kinetic energy - 23At equilibrium, state the energyMaximum kinetic energy
Minimum/zero potential energy - 24Energy graphs
- 25Damped oscillationsOscillations do not go on forever. This happens because of friction. The amplitude of the oscillations decreases as the friction transfers energy away to its surroundings
- 26Damped oscillation graph
- 27Why does damped oscillations not decrease linearlyExponential decay. At first, there is large rapid oscillations hence large air resistance. The slower it vibrates towards the end, the less friction there will be. Frequency does not change
- 28Where damping is usedUsed in the springs of cars (shock absorbers) in order to prevent vibrating up and down on the ride
In buildings to reduce the impact of earthquakes - 29ResonanceThe forced motion of an oscillator characterized be maximum amplitude when the forcing frequency matches the oscillators natural frequency
- 30Three statements that apply to any system in resonanceIts natural frequency is equal to the frequency of the driver
Its amplitude is maximum
It absorbs the greatest possible energy from the driver - 31What happens to resonance when we introduce dampingThe resonance peak becomes broader and the maximum amplitude decreases
- 32Resonance graph
- 33Damped resonance graphs
- 34Examples of appropriate dampingDoors must close back to their original position. If the hinges are too lightly damped, the door will swing back and forth. If the hinges are too heavily damped, it will close too slowly
- 35Critical dampingThe minimum amount of damping required to return an oscillator to its equilibrium position without oscillating
- 36Different types of damping graph
- 37Where resonance is usedMicrowave cooking uses resonance to cause water molecules to vibrate and heat up
MRI uses resonance to see what particular frequencies are absorbed to create an image
Radio and TV uses resonance for its tuning circuitry - 38Big ideas in physicsTake complex problems and reduce it to simpler more manageable problems
Easier to write a mathematical equation that will give numerical answers to problems
Use the solved problem and apply it to other situations
Seek to modify the theory to fit greater range of situations
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- AS level Physics Flashcards on A2 Physics Oscillations, created by Sean Byrne on 20/09/2017.
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- Sean Byrne
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