1) The document discusses different types of waves including transverse, longitudinal, and electromagnetic waves. It defines key wave properties like amplitude, wavelength, frequency, period, and wave speed. 2) Examples are provided to demonstrate how to calculate the frequency, period, and wave speed of different wave types. 3) The document concludes by reinforcing the relationship between wavelength, frequency, and wave speed, providing an example problem to calculate wave speed.

1. Properties of Waves
October 24, 2013

2. Objectives
1.
Recognize the different types of waves
2.
Sketch and identify the different parts of
a transverse wave
3.
Define and calculate the properties of
waves

3. Waves
 Not just the ones you surf on!!!!
 A vibration that moves through space and
time

Light and sound

4. Types of Waves
1.
Transverse waves
2.
Longitudinal or Compressional waves sound
3.
Electromagnetic waves – light

5. Common points
 Crests and Troughs
 Midpoints – horizontal line between the
crests and troughs

6.  Amplitude – distance from the midpoint to
the crest or trough
 Wavelength – distance from one crest to
the next (any consecutive point)

7.  Wave
train – two or more waves in a row

8. 0
x

9.  Frequency – the number of vibrations the
object makes during a certain time interval
(s)


F = Cycles/Seconds
Measured in Hertz (Hz)

10.  Period – time it takes for a complete
vibration


Period = Seconds/Cycles
Period and Frequency are related
Frequency = 1/Period
Period = 1/Frequency

11. Examples
1.
An electric toothbrush completes 90
cycles every second. What is it’s
frequency? What is its period?
2.
Gusts of wind cause the Sears building
in Chicago to sway back and forth,
completing a cycle every ten seconds.
What is its frequency? What is its
period?

12. Problem
A
weight suspended from a spring bobs
up and down over a distance of 20 cm
twice each second. What is its frequency?
Its period? Its amplitude?

13. Waves transport energy
 How much energy depends on wave
speed
 Wave speed = frequency x wavelength

14. Examples
1.
If a train of freight cars, each 10m long,
rolls by you at the rate of three cars each
second, what is the speed of the train?
2.
If a water wave vibrates up and down
three times each second and the
distance between the wave crests is 2m,
what is the wave’s frequency? Its
wavelength? Its wave speed?

15. Problem
A
skipper of a boat notices wave crests
passing his anchor chain every 5s. He
estimates the distance between wave
crests to be 15 m. He also correctly
estimates the speed of the waves. What
is this speed?

16. Frequency and Wave Speed
May 13, 2011