longitudinal and transverse properties.

Some waves both transverse and

longitudinal

Water waves

·Wave travels horizontally

·Particle motion perpendicular and

parallel

15.3 - Periodic waves

Wave pulse: A single disturbance caused by a

one-time excitation.

Periodic wave: A continuing wave caused by a

repeated vibration.

Two types of transverse waves are shown to the right. Concept 1 shows a single wave

pulse in a string. The hand shakes up and down once and the wave pulse moves from

left to right along the string.

Concept 2 shows a periodic wave. The hand moves continuously up and down. In a

periodic wave, each particle in the string moves through a repeated cycle of rising to a

peak, falling to a trough, and then returning again to a peak. The procession of

wavefronts moving down the string is called a wave train.

If you observe a particular crest in the periodic wave, it will move horizontally along the

string over time. This is more apparent in an animation. In a static diagram, the wave

can appear to be stationary, though it is moving down the string as the velocity vector

indicates. Click on the illustration to see an animation.

In this chapter, we focus on waves in which the particles are vibrating in simple

harmonic motion. This vibration will be caused by something (in this case, a hand)

moving or vibrating in simple harmonic motion. The result is the type of sinusoidal wave

you see to the right.

Wave pulse

Caused by a single up and down motion

Periodic wave

Continuing wave caused by a repetitive

vibration

(^296) Copyright 2007 Kinetic Books Co. Chapter 15