5.3 Oscillations Flashcards
What are the conditions for an object to be in simple harmonic motion? (2)
Fixed time period (independent of amplitude)
Acceleration proportional to displacement in the opposite direction
How is the time period of an object moving with SHM determined? (2)
Time a number of oscillations and divide by the number of oscillations to get the time period
Use a fiducial marker at the equilibrium position to clearly indicate where to start and stop measurements
When is the amplitude of oscillations constant?
When no energy is transferred to the surroundings
When is a simple harmonic oscillator at maximum velocity?
The equilibrium position
How is energy transferred over one oscillation of an object moving in SHM? (3)
Total energy remains constant, provided that there are no frictional forces
At amplitude, the KE is zero and potential energy is at its maximum
At equilibrium, KE is at its maximum and potential energy is zero
Define free oscillations
The motion of a mechanical system that is allowed to oscillate without any external forces
Define forced oscillations
An oscillation in which a periodic driver force is applied to an oscillator, causing the object to vibrate at the driving frequency
What is resonance?
The effect caused when the driving frequency is equal to the natural frequency of an object, causing the amplitude of the oscillations to increase dramatically
When do two two oscillating objects have the same natural frequency?
When they are attached to strings of the same length
Give a positive example of resonance
MRI - hydrogen atoms resonate to absorb radio frequency waves
Give a negative example of resonance
A bridge oscillating due to the wind - the wind provides a driving force that can cause the bridge to collapse
What happens to an amplitude-frequency graph as damping increases? (4)
For light damping, the amplitude occurs at the natural frequency
The amplitude of vibration at any frequency decreases
The maximum amplitude occurs at a lower frequency than the natural frequency
The peak on the graph becomes flatter and broader
Give examples of damping (3)
Door damper
Bridge damping
Musical instruments
