# Mechanical Waves.

## Presentation on theme: "Mechanical Waves."— Presentation transcript:

Mechanical Waves

What is a mechanical wave?
A disturbance in matter that carries energy from one place to another. Require a material to pass through called a medium. A medium can be a solid, liquid, or a gas. 3 types of mechanical waves. 1. Transverse waves 2. Longitudinal waves 3. Surface waves

Transverse waves Cause the medium to vibrate at right angles to the direction of wave motion. Wave motion Slinky motion

Parts of a transverse wave
wavelength Rest position node wavelength

Trough – the bottom of a wave.
Crest – the top of a wave. Trough – the bottom of a wave. Wavelength – the distance from crest to crest or trough to trough. Node – where the wave intersects the rest position. Amplitude – distance from the rest position to a crest or trough – measures energy. Frequency – how many times the wave cycles in a given time period. Usually measured in Hertz (Hz) – cycles per second Low frequency High frequency

Wavelength and Frequency
These 2 are related As one increases, the other decreases. Low frequency, large wavelength High frequency, small wavelength

Longitudinal Waves Compression waves
Move the medium the same direction as the wave. Made from compressions and rarefactions Wave motion Slinky motion

Surface Waves Travel along the surface separating 2 media.
Ocean waves travel between water and air Have characteristics of both longitudinal and transverse waves. Transverse part causes up and down motion. Longitudinal part causes back and forth motion.

Wave Speed Speed = frequency X wavelength n f l n = speed (m/s)
f = frequency (Hz) l = wavelength (m)