Introduction to Waves

1
3/29/06 Introduction to Waves Sound Questions
about RHR Questions about Faradays Law/Lenzs
Rule
No New Reading for Friday
2
Right Hand Rules Review
Direction of Magnetic FIELD
Direction of Magnetic FORCE
3
Another Example of Faradays Law Lenzs Rule
Eddy-Current Braking A magnetic field points
into the page as shown. For example, this field
could be created by an electromagnet or between
the poles of permanent magnets. A metal pendulum
swings into the magnetic field. What happens to
the motion of the metal pendulum? Why does this
happen?
x x x x x x x x x
x x x x x x x x x
4
Poster Presentation How Computers Work? Date
Monday May 1 (during lab time). Work in
Pairs Moved from Monday April 23
Possible Topics?
Webcam/Digital Camera
Monitors
Speaker/Microphone

Writing Reading
Scanners
Magnetic Hard Drive/Memory
Printers Laser/Inkjet

Optical DrivesCD/DVD
Read Only Recordable/Rewritable
Input Devices Keyboard/Mouse
Lasers
Flash Memory
Random Access Memory (RAM) Dynamic/Static
Wired Networks Modems/Firewire/USB
Circuits/Processor Diodes, Transistors
Wireless Networks
Power Supplies AC ? DC Rechargeable Batteries
5

• Exercise Vibrations into Sound
• Obtain Rubber Band
• Hold rubber band in two hands, slightly stretched
• Pluck Rubber Band Look Listen
• Stretch Rubber Band a little more Pluck Look
  Listen
• Repeat Several Times

• Exercise Standing Waves, Wavelength, Frequency,
  Wave Speed
• Work in Pairs
• Borrow long slinky
• Follow Instructions

Questions What are the various standing wave
patterns you saw? What is relationship between
frequency and wavelength? What happens if you
change the length?
Questions What is sound? How does it connect
to motion? How does it connect to harmonic
motion?