Definitions [8]
Define the term oscillation.
Oscillation refers to a complete 'to and fro' motion of the body along its course.
Define the frequency of simple harmonic motion.
The number of oscillations produced by the particle per second is called frequency. It is denoted by f. SI unit for frequency is s−1 or hertz (Hz).
Mathematically, frequency is related to the time period by f = `1/"T"`
Define the time period of simple harmonic motion.
Time period: The time period is defined as the time taken by a particle to complete one oscillation. It is usually denoted by T. For one complete revolution, the time taken is t = T, therefore,
`ω"T"` = 2π ⇒ T = `(2π)/ω`
Any function that repeats itself at regular intervals of its argument is called a periodic function.
The physical quantity which represents the position and direction of motion at any instant of the particle executing SHM is called phase.
The constant φ in the equation of SHM x = Acos(ωt + ϕ) is called phase constant or initial phase.
If the restoring force/torque acting on a body in oscillatory motion is always directly proportional to its displacement from the equilibrium position and directed towards it, then the motion is called simple harmonic motion (SHM).
Define forced oscillation. Give an example.
The body executing vibration initially vibrates with its natural frequency and due to the presence of external periodic force, the body later vibrates with the frequency of the applied periodic force. Such vibrations are known as forced vibrations.
Example: Sound boards of stringed instruments.
