Periodic motion definitions Flashcards
Amplitude
the maximum displacement of an oscillating object from its equilibrium position.
Angular displacement
the angle an object in circular motion turns through. If its time period is T and its frequency is f, its angular displacement in time t, in radians = 2πft = 2πt/T.
Angular speed ω
the rate of change of angular displacement of an object in circular (or orbital or spinning) motion.
Angular frequency ω
essentially the same as angular speed, for an object oscillating at frequency f in simple harmonic motion, its angular frequency = 2πf.
Centripetal acceleration
acceleration directed towards the centre of circular motion
Centripetal force
the resultant force on an object that moves along a circular path, directed towards the centre of the circle
Damped oscillations
oscillations that reduce in amplitude due to the presence of resistive force such as friction or drag.
Light damping
Damping which causes the amplitude of the oscillations to gradually decraese
Heavy damping
damping that results in the system slowly returing to equilibrium without oscillating.
Critical damping
Damping that results in the system returning to the equilibrium position in the least possible time without oscillating.
Dissipative forces
forces that transfer energy that is wasted.
Equilibrium
state of an object when at rest or in uniform motion.
Forced vibrations
vibrations (oscillations) of a system subjected to an external periodic force.
Free vibrations
vibrations (oscillations) where there is no damping and no periodic force acting on the system, so the amplitude of the oscillations is constant.
Frequency
of an oscillating object is the number of cycles of oscillation per second.
Natural frequency
the frequency of free oscillations of an oscillating system (no damping and no periodic force acting on the system)
Periodic force
a force that varies regularly in magnitude with a definite time period.
Resonance
the amplitude of vibration of an oscillating system subjected to a periodic force is largest when the periodic force has the same frequency as the resonant frequency of the system.
Resonant frequency
the frequency of an oscillating system in resonance (when the amplitude of oscillation is largest).
Simple harmonic motion
motion of an object if its acceleration is proportional to the displacement of the object from equilibrium and is always directed in the opposite direction to the displacement (towards the equilibrium position).
Time period
time taken for one complete oscillation
Uniform circular motion
motion of an object moving at constant speed along a circular path.
