What is a wave? A wave is simply a movement of energy that travels through a medium…

Types of Waves Slide 15-8 2

How to graph a wave?

Do U get it? Assume V ~ constant 1) Quiet sound, low frequency: 2) Quiet sound, high frequency: 3) Loud sound, low frequency: 4) Loud sound, high frequency:

Main Waves Types: Transverse Transverse waves are when the displacement is at right angles to the direction of the wave… Displacement Direction Examples include waves in water, strings, earthquakes…

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Longitudinal waves Displacement Longitudinal waves are when the displacement is parallel to the direction of the wave… Direction

Compare a longitudinal wave in a slinky to a sound wave in a tube:

A = pressure amplitude = max. change in pressure very small for common sounds ( 3x10-2 Pa) Loudness is related to pressure amplitude

Frequency (Pitch) of Sound Waves: number of cycles per second Healthy young ears can hear frequencies between: 20 Hz 20,000 Hz Infrasonic Which end do we lose with age? Ultrasonic Pure tone – a single frequency sound (most sounds are composed of many frequencies)

Sound can travel through any kind of matter, but not through a vacuum. The speed of sound is different in different materials; in general, it is slowest in gases, faster in liquids, and fastest in solids. The speed of sound is different in different materials; in general, it is slowest in gases, faster in liquids, and fastest in solids. The speed depends somewhat on temperature, especially for gases. The speed depends somewhat on temperature, especially for gases.

SOUND WAVES Sound is a longitudinal wave produced by a vibration that travels away from the source through solids, liquids, or gases, but not through a vacuum. The speed of sound is independent of the pressure, frequency, and wavelength of the sound. However, the speed of sound in a gas is proportional to the temperature T. The following equation is useful in determining the speed of sound in air v = 331 + 0.6 T Units: m/s Where 331 is the speed of sound in m/s at 0°C, and T is the temperature in °C

Which of the following increases when a sound becomes louder? A) frequency B) wavelength C) amplitude D) period E) velocity

Which of the following increases when a sound becomes higher in pitch? A) frequency B) wavelength C) amplitude D) period E) velocity

Characteristics of a Wave On this wave, the wavelength and amplitude (in that order) are represented as segments A. BD and HC BD and IC CE and IC CG and HC None of these  

Period vs Frequency If a spring oscillates up and down 8 times in 2 seconds, what is the period? 0.25 s 2 s 4 s 8 s 16 s Follow-up: What is the frequency?

Period vs Frequency If a pendulum oscillates back and forth 4 times in 12 seconds, what is the frequency? 0.33 Hz 3 Hz 4 Hz 12 Hz 48 Hz Follow-up: What is the period?

Speed of a Wave Waves in the ocean measure about 5m apart, and about 1.5m tall. They crash on the shore once every 2.5 seconds. What is the approximate speed of these ocean waves? 0.6 m/s 2 m/s 2.6 m/s 3.75 m/s 12.5 m/s 5m 1.5m

Speed of a Wave A sound wave with a wavelength 0.725m, a period of 5 × 10-4 s, and a frequency of 2,000 Hz traveling through water can go 4.35 km in 3 seconds. What is the speed of the sound wave. 3.625 × 10-4 m/s 1.45 m/s 0.24 m/s 8700 m/s None of these

The time to make 1 cycle, is also the time it takes the wave to travel 1 λ.

 

Part 1?