Definition:Simple Harmonic Motion
This page is about simple harmonic motion. For other uses, see harmonic.
Definition
Consider a physical system $S$ whose motion can be expressed in the form of the following equation:
- $x = A \map \sin {\omega t + \phi}$
where $A$ and $\phi$ are constants.
Then $S$ is in a state of simple harmonic motion.
Amplitude
The parameter $A$ is known as the amplitude of the motion.
Phase
The expression $\omega t + \phi$ is known as the phase of the motion.
Period
The period $T$ of the motion of $S$ is the time required for one complete cycle:
- $T = \dfrac {2 \pi} \omega$
Frequency
The frequency $\nu$ of the motion of $S$ is the number of complete cycles per unit time:
- $\nu = \dfrac 1 T = \dfrac \omega {2 \pi}$
Also defined as
Simple harmonic motion can also be characterised in the form:
- $x = A \map \cos {\omega t + \phi}$
From Sine of Angle plus Right Angle:
- $\map \sin {\omega t + \phi + \dfrac \pi 2} = \map \cos {\omega t + \phi}$
the two forms can be seen to be equivalent.
Also known as
Simple harmonic motion can also be referred to as simple harmonic oscillation or simple harmonic vibration.
It is commonly abbreviated it SHM.
Also see
- Results about simple harmonic motion can be found here.
Sources
- 1972: George F. Simmons: Differential Equations ... (previous) ... (next): $\S 3.20$: Vibrations in Mechanical Systems
- 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): harmonic motion
- 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): simple harmonic motion
- 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): harmonic motion
- 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): simple harmonic motion