Periodic Motion Notes

Types of Periodic Motion

1. Transverse Motion

   • Vibration/wave acts perpendicular to the rest axis.
   • Resembles a sine wave, oscillating up and down around the rest axis.

2. Longitudinal Motion

   • Vibration/wave acts parallel to the rest axis.
   • Example: a slinky being pushed back and forth, showing extensions and contractions.

3. Torsional Motion

   • Vibration/wave acts around the rest axis.
   • Example: spinning a string, demonstrating torsion.

Definitions of Wave Characteristics

1. Amplitude (A)

   • Displacement of a wave from the rest axis.
   • Measured as the distance from the rest axis to either the crest or trough.

2. Period (T)

   • Time taken to complete one full cycle (back and forth).
   • Measured in seconds.

3. Frequency (f)

   • Number of cycles (waves) that occur per second.
   • Measured in hertz (Hz).

4. Phase

   • Refers to whether waves are in phase or out of phase.
   • Example:
     • In Phase: Windshield wipers move together.
     • Out of Phase: Wipers oppose or do not move together (either going apart or together).

Period vs Frequency

• Period (T): Time taken for one cycle (seconds)
• Frequency (f): Number of cycles per second (Hz)
• Relationship:
  • Inverse of one another:
    • Formula:
      • [ f = \frac{1}{T} ]
      • [ T = \frac{1}{f} ]

Exercises

• Questions associated with this note are 1 to 3 in your yellow duotangs.