WEEK 9 (Mechanical oscillation) Flashcards
What is Hook’s law and what does it show?
F = -kx
Restoring force always pushes or pulls the object towards the equilibrium position
What is amplitude?
Maximum distance of the object from the equilibrium position
What is period?
The time it takes object to move through one complete cycle of movement
What is frequency?
The number of complete cycles or vibration per unit of time
What is ‘Damped oscillation’?
We always have a force of FRICTION, it reduces energy of the object and movement becomes damped
What is the difference between Harmonic movement and waves?
Harmonic movement = motion of mass
Waves = motion of disturbance
What are the two types waves?
Transverse wave & Longitudinal wave
Where are transverse waves found?
- solid objects
- liquid
- gas interface
What happens when waves travel from one media to another?
- Amplitude, wavelength and velocity changes
- Frequency & Period doesn’t change
What is the difference between ‘In phase’ and ‘Out of phase’
In phase - Constructive interference
Out of phase - Destructive interference
What does the speed of sound in a fluid depend on?
The fluid’s compressibility and inertia
Define Bulk modulus
The ratio of the change in pressure to the resulting fractional change in volume
Speed of sound depends on _______________
Temperature
The equation for sound including Young’s modulus is valid only for what?
A thin, solid rod
What is the average intensity of a wave?
The average intensity I of a wave on a given surface is defined as the rate at which energy flows through the surface, ΔE/Δt, divided by the surface area A . The direction of energy flow is perpendicular to the surface at every point.
What is the relative intensity of a sound called?
Intensity level/Decibel level
The loudest tolerable sounds have intensities about _________________ times greater than the faintest detectable sounds.
1.0 x 1012
Where does Decibel come from?
Decibel comes from Alexander Graham Bell (1847–1922), inventor of telephone
Describe an application of the Doppler effect
It is possible to measure the speed of the blood flow in the body with a device called an ultrasonic flow meter, which makes use of the Doppler effect. The flow speed is found by comparing the frequency of the waves scattered by the flowing blood with the incident frequency
What is louder, long wavelength & low frequency or small wavelength & high frequency?
Small wavelength & High frequency
When do vibration amplitude reach their maximum?
Its amplitude reaches a maximum when the frequency of the driving force equals the natural frequency of the system f0, called the resonant frequency of the system. Under this condition, the system is said to be in resonance
What are three basic tasks of the auditory system (ear):
- deliver acoustic stimulus to the receptors
- transduce the stimulus from pressure to electric signals
- process electric signals to indicate pitch, loudness and location
