5.3 Oscillations Flashcards
what is the definition of displacement (in terms of oscillations)?
displacement is the distance an object move from its equilibrium/rest position, may be positive or negative (in metres)
what is the definition of amplitude?
amplitude is the maximum displacement from the equilibrium position and will always be positive (in metre)
what is the definition of period?
period is the time taken for 1 complete pattern of oscillation at any point (in seconds)
what is the definition of frequency?
frequency is the number of oscillations per unit time at an point, number of cycles per second (in Hz)
what is the definition of phase difference?
phase difference,Φ, is the fraction of a complete cycle or oscillation between 2 oscillating points
what is the formula for angular frequency?
ω = 2π / T or ω = 2πf
what is the difference between angular velocity and angular frequency? which applies to circular motion and which applies to oscillations?
they have the same formula but angular frequency is the magnitude of the vector quantity of angular velocity, they are both measure in rad s^-1 but…
angular velocity –> circular motion (vector)
angular frequency –> oscillations (scalar)
what is the equation of simple harmonic motion?
a = -ω^2x
where a = acceleration
ω = angular frequency
x = displacement
what is simple harmonic motion?
when an object oscillates and the acceleration of the object is directly proportional to its displacement and acts in the OPPOSITE direction to he acceleration (towards the fixed midpoint)
what is the restoring force in oscillations (think of a pendulum)?
the restoring force acts in the opposite direction to the displacement (brings it back to the middle)
how do you determine the period/frequency of a simple harmonic oscillator?
- to work out the frequency use 1 / T
- the best place to time from is in the middle because there is less error than recording at maximum displacement because at max displacement the velocity is slower as its changing direction and spends more time there so timing at that point increases inaccuracy
- you need to time for 10 oscillations then work out the mean and divide by 10
in SHM, are frequency and period dependent on the amplitude?
no, they DO NOT depend on the amplitude
what is an isochronous oscillator?
in SHM, the frequency and period are independent of the amplitude (they’re constant for a given oscillation) so a pendulum clock will keep ticking in regular time intervals even if its swing becomes very small, this kind of oscillator is called an isochronous oscillator
when is the velocity max in a swinging pendulum?
at the midpoint (where x = 0) most KE
when is the velocity 0 in a swinging pendulum?
when displacement is max (at the ends of the swing)
when is the displacement max in a swinging pendulum?
at the ends of the swing