Unit 7 Waves & Beaches
Topic 2 Calculating Wave Properties Wave terms: Still water level – water level when the surface is flat and smooth with no waves Crest – the highest point of a wave Trough – the lowest point of a wave below the still water mark. Amplitude – distance from rest to crest or rest to trough
Wave terms continued: Wavelength – horizontal distance from crest to crest Period – the time in seconds that it takes for one complete wave to pass a fixed point. Frequency – the # of wave crests that pass a fixed point per unit of time Wave speed – The speed of the wave in a certain direction expressed as distance per unit of time.
Speed = wavelength / period Wave Calculations We can calculate the speed (v) of a wave from its wavelength (λ) and period (T). Speed = wavelength / period v = λ / T If a wave takes 5 seconds to have a wavelength of 50 meters, what is the speed of the wave? v = 50 m/5 s v = 10 m/s
More Wave Calculations If a waves travels at 4 m/s and travels for 30 seconds, what is it’s wavelength? How long would it take if a wave travels at a speed of 6 m/s for 120 m?
More Wave Calculations Frequency of a wave = 1wave / period f = 1 wave/T If a wave travels for 6 seconds, what is it’s frequency?
Calculations… When the crest of wave A passed point P, the watch read 0.00 seconds. When the crest of wave B passed point P, the watch read 10.00 seconds. What is the period? What is the speed? c. What is the frequency?