Ch17: Oscillations Flashcards
Define displacement.
distance from the equillibrium position.
Define amplitude.
maximum displacement from the equilibrium position.
Define period.
time taken to complete one full oscillation.
Define frequency.
Number of oscillations per unit time.
Define simple harmonic motion.
When the acceleration of the oscillating object is directly proportional to its displacement, in the opposite direction, tending toward the equilibrium position.
Define angular frequency.
A quantity equal to the product of 2π and frequency.
Describe the graph of displacement against acceleration for an object in simple harmonic motion.
What is its gradient?
A straight line of negative gradient, through the origin. Gradient of -ω²
What are the two equations for displacement, when do you use each?
x=Acos(ωt) and x=Asin(ωt)
Use cos when the objects begins at it’s amplitude and sin when it begins in the equilibrium position.
When does an pendulum in simple harmonic motion have greatest velocity?
At the bottom.
When does a pendulum in simple harmonic motion have greatest acceleration?
At the top.
When does a pendulum in simple harmonic motion have greatest energy?
All the time, total energy is conserved, but is transferred between types.
What is damping? What is an example?
An oscillation is damped when an external force on the oscillator has the effect of reducing the amplitude of its oscillations. A pendulum in air will experience air resistance until it comes to rest.
What is light damping?
When the amplitude of an oscillator gradually reduces with time but it’s period is virtually unchanged.
When does resonance occur?
When driving frequency = natural frequency of the forced oscillator
