Mechanical Waves: These travel through a material medium.
Electromagnetic Waves: EM waves do not require a material medium to exist.
Matter or Quantum Mechanical Waves: These describe the motion of elemental particles (electrons, protons, etc.) on the atomic level. We won't investigate them in this course.
We also classify waves based on how they move:
Transverse Waves: The particles of the wave move perpendicular to the motion of the wave.
Longitudinal Waves: The particles of the wave move parallel to the motion of the wave. This is done through compression and rarefaction (expansion), i.e., the wave is transmitted by pressure changes.
We describe a wave with the following characteristics:
Amplitude (A): How tall the wave is at its maximum height.
Wavelength (λ): The distance between "repeating" points on the wave, such as top-to-top.
Wave speed (v): How fast the wave is moving.
Period (T): The time it takes to go through a full oscillation.
Frequency (f): The number of oscillations that occur per second. [The unit for this is the hertz (Hz) where 1 Hz = [1/1s]. Thus, f = [1/T] and T = [1/f].]
Because speed, frequency, and wavelength are all related, v = λf .
We can find the height (or pressure differential if it's a longitudinal wave) with the following equation:
y(x,t) = Asin(kx − ωt).
x is the horizontal location we are considering.
t is the time we are looking at the wave.
k is the angular wave number and is connected to the wavelength:
ω is the angular frequency and is connected to the period (which is connected to the frequency):
⇔ ω = 2π·f.
Intro to Waves
Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.
This book includes a set of features such as Analyzing-Multiple-Concept Problems, Check Your Understanding, Concepts & Calculations, and Concepts at a Glance. This helps the reader to first identify the physics concepts, then associate the appropriate mathematical equations, and finally to work out an algebraic solution.