h.m.
This definition can be expressed mathematically as.
a = -(a constant).x.
where x is the displacement of the body from the equilibrium position. The magnitude of the constant is equal to a/x or f/mx, where m is the mass of the oscillating body and F is the restoring force. We would therefore expect the value of the constant for a given oscillation to depend on:.
u The restoring force per unit displacement.
u The mass of the oscillating body.
The pendulum:.
A simple pendulum consists of a heavy mass called a BOB suspended from a fixed support by a light string. When displaced to an initial angle and released, the pendulum will swing back and forth with periodic motion. The period of the pendulum is defined as the time for the bob to swing through a complete cycle and return to its starting position (mean position). This is called an oscillation. The pendulum has been used as a precise time measuring device since early in recorded history. It is said that Galileo used to swing of a candle chandelier to explain the motion of a pendulum in the early 1600's.
As seen with the example of SHM already, namely the spring with a mass at the end.
The diagram below shows the basic working of a simple pendulum:.
.
Another useful quantity used to describe periodic motion is the .
frequency of oscillation. The frequency f of the oscillations is the number of oscillations that occur per unit time and is the reciprocal of the period, f = 1/T. Similarly, the period is the inverse of the frequency, T = l/f. Thus an oscillation is a repeated periodic motion, vibration or variation in the state of an object. The time for one oscillation is called the PERIOD. The number of oscillations in a given time (usually a second) is called the FREQUENCY (vibrations per second are given the unit of the hertz or Hz.). Another example of an oscillating body is exhibited when a child is swinging to and fro on a swing. The maximum distance that the mass is displaced from its equilibrium position is defined as the AMPLITUDE of the oscillation.
