Vibrations

The Movement of Energy

Music

WavesA transfer of energy over a distance in the form of a disturbance

Wave originate from objects that are vibrating

This is cool so why not…

https://www.youtube.com/watch?v=Ude8pPjawKI

Three Types of Vibrations

1. Transverse Vibrations Occurs when an object

vibrates perpendicular to its axis

ie. Guitar strings

Transverse Waves

http://surendranath.tripod.com/Applets/Waves/Twave01/Twave01Applet.html

2. Longitudinal Vibrations Occurs when an object

vibrates parallel to its axis

Ie. Shocks on a car or mountain bike

Longitudinal Waves

http://surendranath.tripod.com/Applets/Waves/Lwave01/Lwave01Applet.html

2. Torsional Vibrations Occurs when an object

twists around it’s axis Ie. Washing machine

Let’s hit the hallway…

Describing Vibrations

Cycle Occurs with a repeating event One cycle – when an object returns

to the place it started and it is moving in the same direction

Describing Vibrations

Rest Position Midway point between extremes

in a cycle

Describing Vibrations

Amplitude (A) Displacement of object to either side

of it's rest position

Describing Vibrations

Frequency (f) The number of cycles per second Measured in Hertz (Hz)

Describing Vibrations

1 Hz = 1 cycle per second

Describing Vibrations

Period (T) The time required for one cycle Measured in seconds

Formulas

f = 1 T = 1 T f

f = # of cycles T = Time Time # of cycles

Sample Problem

If an electron vibrates back and forth with a frequency of 60 Hz, how long does it take to undergo one cycle?

Comparing Vibrations

In Phase VibrationsPass the rest point at the

same timeSame period of vibration

Comparing Vibrations

Out of Phase VibrationsDifferent period or same

period but do not pass through the rest point at the same time