Mechanical Waves What is a mechanical wave A

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

• 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)