Option B4 Flashcards
Forced vibrations and resonance
What is
Natural frequency of vibration ?
When something is disturbed and then left to oscillate without further interference, it is said to oscillate at its natural frequency of free vibration.
What is
Free vibration?
What is
Damping?
What is
Q Factor?
Q Factor is a quantity used to measure the degree of damping
Q factor is approximately equal to the number of oscillations that are completed before damping stops the oscillation.
What is the formula
of calculating Q Factor?
What is
the relationship between
Forced oscillation, periodic stimulus
and the driving frequency?
A forced oscillation occurs when an external oscillating force (periodic stimulus) acts on another system tending to make it oscillate at a frequency that may be different from its natural frequency. e.g. Child on the swing. Frequency of the external oscillating force is driving frequency.
What is
Resonance ?
When the driving frequency of an external periodic stimulus equals to the natural frequency, energy of the external force is all used to overcome the resistive force of damping, it results in oscillation with large amplitude, the effect is called resonance.
Describe Underdamping or light damping
Describe
Critical Damping
Describe
Overdamping damping
Graphically describing the variation of the amplitude of vibration with driving frequency of an object close to its natural frequency of vibration when there is no damping
Graphically describing the variation of the amplitude of vibration with driving frequency of an object close to its natural frequency of vibration when there is damping
Describing the phase relationship between driving frequency and forced oscillations
Describe the Useful effects
of resonance
Useful effects of resonance
- used in microwave oven to warm food
- radio uses resonance to turn into one specific station and not another
- Quartz oscillator is a quartz crystal that can be made to vibrate at a specific frequency which provides accurate clocks for microprocessor systems.
Describe the Destructive effects
of resonance
Destructive effects of resonance
- Vibration of machinery – for example, a washing machine with the spinner running , parts of vechicles vibrates with the engine, etc.
- Earthquakes may well affect buildings that have natural frequencies close to the frequencies of the earthquake.
- Strong winds or currents can cause dangerous resonance in structures such as bridges and towers
What is
the maximum potential energy
in an oscillation ?
