WAVES

WHAT IS A WAVE?

• Wave- a wave is any disturbance from any

equilibrium position which travels or propagates itself over time from one place to another.

- it carries energy through matter or space.

Parts of a Wave

crest

Speed = wavelength x frequency

TYPES OF WAVES

• Mechanical Waves- waves that need a medium in order to

propagatee.g. sound waves, water waves, spring waves• Electromagnetic Waves

- waves that do not require a medium in order to propagatee.g. light waves, radio waves

CLASSIFICATION OF WAVES

• Transverse Waves- a waves that moves matter in direction

perpendicular to the direction of the wave’s motion• Longitudinal Waves

- the movement of the particle is along the direction of the wave.• Surface Wave

- are combination of transverse and longitudinal waves

PROPERTIES OF WAVES

• Reflection- the bouncing off of waves as it hits a

material.

Law of Reflection1. The angle of

incidence is equal to the angle of reflection

i = r2. The incident ray, the reflected ray and the normal line lie on a single plane.

• Refraction- the bending of waves as is pass through a

medium

• Diffraction- the ability of the wave to travel around

corners or obstacles in their path.

• Interference- when two waves meet at a point, the

resulting displacement of that point will be the sum of the displacements produced by each of the waves.1. Constructive interference

- If the crests of one wav meet the crests of the other, and the troughs of one of the waves meet the trough of the other.

2. Destructive interference- if the crests of one of the wave meet the troughs

of the other

EXAMPLE

• What is the angle of reflection of water waves if the incident angle is 250?• Wave A with amplitude of 10 cm meets wave B

with the same wavelength but with amplitude half of wave A. If a crest of a wave A meets a trough of wave B, what is the amplitude of the resultant wave.

• Calculate the speed of a sound wave whose wavelength is 15 meters and whose frequency is 15 Hz?

• A swimmer notices that the water wave crests pass his body every 3 second. The distance between two crests base from his rough estimate is about 4 meters. How fast are the waves traveling.

• Extreme waves along ocean waters, sometimes referred to as freak waves or rogue waves, are a focus of much research and study among scientists. Several merchant ships reports rogue waves which are estimated to be 25 meters high and 26 meters long. Assuming that these waves travel at speeds of 6.5 m/s, determine the frequency and the period of these waves.