CH17 - Oscillations Flashcards
(19 cards)
What is displacement X
The distance from the oscillator to the equilibrium
What is Amplitude , A
The maximum displacement to the equilibrium
What is angular frequency, W
The rate of change of angular displacement
What are 2 defining characteristics of simple harmonic motion
The acceleration is proportional to the displacement
The acceleration is always directed to the equilibrium position
What is the gradient of an a, x graph
-W^2
What formula is used for displacement x, if at t=0 the oscillator is at the amplitude.
X = Acos(wt)
What formula is used for displacement x, if at t-0 the oscillator is at the equilibrium.
X = ASin(wt)
What may cause amplitude to not remain constant?
Energy transferred to the surroundings
What is damping
An oscillation is damped when an external force that acts on the oscillator has the effect of reducing the amplitude of its oscillations.
What is a free oscillation and give an example
When a mechanical system is displaced from its equilibrium position and allowed to oscillate without any external forces
Example - Pendulum released from amplitude
What is a Forced oscillation and give an example
A periodic driver force is applied to an oscillator during oscillations
Example - pendulum with motor
When does resonance occur
Resonance occurs when the frequency of the driving force matches the natural frequency
What happens when resonance occurs
The amplitude of the oscillation increases considerably
What will happen to a system at resonance if it is not damped
If the system is not damped, the amplitude will increase to the point it fails
What happens at resonant frequency (energy)
The greatest possible transfer of energy from the driver to the forced oscillator occurs
What happens to amplitude/ frequency graph when damping occurs
Shifted to the lift and down
Peak is more flatter
How does resonance in a microwave occur and heat up things
The driving frequency of the EM radiation, matches the natural frequency of the water molecules
This causes resonance
it increases the amplitude and the kinetic energy of the molecules of the food causing them to heat up
When is potential energy maximum and minimum
When is kinetic energy maximum and minimum
Potential energy is maximum at maximum displacement and minimum at x=0
Kinetic energy is maximum at x=0 and minimum at maximum displacement
