Physics

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Periodic motion:

Any motion in which all the parameters of motion are repeated after a definite rime interval, is called as periodic motion. The time which elapses between successive passages in the same direction through any point is termed the periodic time, or the period, of the motion.
The number of periods comprised in one second is called the frequency; thus, if T is the period, and n is
the frequency of a periodic motion, we have `n = 1/T`.
The motion of the hands of a clock is periodic, the period of the motion of the minute hand being one hour, or 3600 seconds. The bob of a pendulum moves periodically, the period being equal to the time of one complete (to and fro) oscillation. Periodic motion can be along any path. Very often the body undergoing periodic motion has an equilibrium position somewhere inside its path.

`text(Oscillatory motion:-)` If a particle moves to and fro on the same path, the motion is said to be oscillatory motion. A periodic motion may not be oscillatory, for example planetary motion, the hands of a clock.

Any motion in which all the parameters of motion are repeated after a definite rime interval, is called as periodic motion. The time which elapses between successive passages in the same direction through any point is termed the periodic time, or the period, of the motion.
The number of periods comprised in one second is called the frequency; thus, if T is the period, and n is
the frequency of a periodic motion, we have `n = 1/T`.
The motion of the hands of a clock is periodic, the period of the motion of the minute hand being one hour, or 3600 seconds. The bob of a pendulum moves periodically, the period being equal to the time of one complete (to and fro) oscillation. Periodic motion can be along any path. Very often the body undergoing periodic motion has an equilibrium position somewhere inside its path.

`text(Oscillatory motion:-)` If a particle moves to and fro on the same path, the motion is said to be oscillatory motion. A periodic motion may not be oscillatory, for example planetary motion, the hands of a clock.

Period and frequency

Any motion that repeats itself at regular intervals of time is called periodic motion. The smallest interval of time after which the motion is repeated is called its period. Let us denote the period by the symbol T. Its SI unit is second. For periodic motions, which are either too fast or too slow on the scale of seconds, other convenient units of time are used. The period of vibrations of a quartz crystal
is expressed in units of microseconds (`10^(-6) s`) abbreviated as μs. On the other hand, the orbital period of the planet Mercury is 88 earth days.
The reciprocal of T gives the number of repetitions that occur per unit time. This quantity is called the frequency of the periodic motion. It is represented by the symbol ν . The relation between v and T is

` v = 1/T`

The unit of ν is thus `s^(-1)`. After the discoverer of radio waves, Heinrich Rudolph Hertz (1857-1894), a special name has been given to the unit of frequency. It is called hertz (abbreviated as Hz). Thus,

1 hertz = 1 Hz =1 oscillation per second =`1s^(-1)`

Any motion that repeats itself at regular intervals of time is called periodic motion. The smallest interval of time after which the motion is repeated is called its period. Let us denote the period by the symbol T. Its SI unit is second. For periodic motions, which are either too fast or too slow on the scale of seconds, other convenient units of time are used. The period of vibrations of a quartz crystal
is expressed in units of microseconds (`10^(-6) s`) abbreviated as μs. On the other hand, the orbital period of the planet Mercury is 88 earth days.
The reciprocal of T gives the number of repetitions that occur per unit time. This quantity is called the frequency of the periodic motion. It is represented by the symbol ν . The relation between v and T is

` v = 1/T`

The unit of ν is thus `s^(-1)`. After the discoverer of radio waves, Heinrich Rudolph Hertz (1857-1894), a special name has been given to the unit of frequency. It is called hertz (abbreviated as Hz). Thus,

1 hertz = 1 Hz =1 oscillation per second =`1s^(-1)`

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