15.12 - Summary
Mechanical waves are oscillations in a medium. This chapter discussed traveling
waves: disturbances that move through a medium.
There are two basic wave types. In a transverse wave, the particles in the medium
oscillate perpendicularly to the direction that the wave travels. In a longitudinal
wave, the particles oscillate parallel to the direction the wave travels. Some waves,
such as water waves, exhibit both transverse and longitudinal oscillation.
A wave can come as a single pulse, or as a periodic (repeating) wave. In this
chapter, we analyze periodic waves whose particles oscillate in simple harmonic
motion.
The amplitude of a wave is the distance from its equilibrium position to its peak. The
wavelength is the distance between two adjacent peaks. The period is the time it
takes for a particle to complete one cycle of motion, for example, moving from peak
to peak. Frequency is the number of cycles that are completed per second.
Wave speed is the speed with which a wave moves through a medium. It is equal to
the wavelength of the wave times its frequency.
The wave speed in a string increases with the tension of the string and decreases with the string’s linear density.
T = 1/f
Wave speedWave speed in a string