4.4 Simple Harmonic Motion Flashcards
Simple harmonic motion (definition and equation)
“The acceleration is directly proportional to the displacement and is always acting towards the fixed position”
a=-w^2.x
Damping
“Restive force which opposes motion and so causes the amplitude to decrease”
Resonance
“A vibrating system or external force drives another to oscillate with greater amplitude at specific frequencies”
Free vibrations
“No energy is transferred to or from the system, thus amplitude remains fixed”
Forced vibrations
“Forced to oscillate at the frequency of an external oscillator”
Simple harmonic motion equation
a=-w^2x
Rads equation
W=2.pi.f
Displacement equation
x=Acoswt
Max acceleration equation
a=w^2A
Force and acceleration signs depending on positive or negative displacement
Positive displacement: force (-) acceleration (-)
Negative displacement: force(+) acceleration (+)
Light damped
The displacement will vary with time, gradually decreasing to zero
Heavily damped (overdamping)
No oscillations occur and slowly returns to the equilibrium position
Graph: decreasing exponentially to 0 in T
Critically damped
Damped in 1/4 of a T period minimum
