1. What is sound? 2. Define vibration 3. Explain the relationship between

wave and vibration. 4. What is the nature of sound? 5. Discuss echo and Reverberation

Sound speed

MEASURES OF A WAVE WAVELENGHT (λ) - Is the distance that wave moves for every complete repetition of its motion.

Period – the time it takes a point in the wave to cover a distance equal to wavelength

Frequency - refers to how often the particles of the medium vibrates when a wave passes through the medium

The frequency of a wave

We can substitute 1/T with frequency (f)

The sound of an oboe playing in the middle A note has a frequency of 440 Hz. Find the wavelength of this note.( the speed of sound in air at room temperature is 347 m/s)

The speed of a wave through a specific medium is determined by the square root of the ratio of an elasticity factor to an inertia factor

The speed (v) of a transverse wave is stretched string is given by the formula:

The waves carried by a stretched string increase when tension increases

Speed is inversely proportional to the inertial factor mass per unit length “ linear density”

In the case of a longitudinal wave travelling through a solid rod, the speed of the wave is given as

Y = Young’s modulus of elasticity of the solid rod (elasticity factor)

The speed of a wave in liquid is given by the formula

An increase in the pressure will decrease the volume . A decrease in the volume will increase the density

The speed v of a longitudinal wave in a gas

R= is the gas constant = 8.315 joules per mole kelvin ( J/mole.K)M= molar massT= absolute temperature= “ gamma” specific heat ratio

What will be the speed of transverse waves along a steel violin string that is 75.0 cm long and has a diameter of 0.500 mm if a tension of 200 N is applied on the string? The density of steel is 7800 kg/m3 and its Young’s modulus is

20 x 1010 N/m2

One end of a clothesline is tied to a post and the other is stretched with a tension of 150 N. The clothesline is 4.00 m long and has a mass of 0.340 kg.

1. What is the mass per unit length of the clothesline?

2. What is the speed of transverse waves on the wire?

3. If the free end is pulled up and down at the rate of 30 times per second, what is the wavelength of transverse waves on the string?

4. If the tension is increased to 300 N, what should be the frequency so that waves produced on the string have the same wavelength as the number 3?

assignment A trumpet produces a sound wave that is

observed travelling at 350 m/s with a frequency of 1046.50 Hz. Calculate the wavelength of the sound wave.

On your class wave machine, you have a string of mass 350 g and length 2.3 m. You would like to send a wave along this string at a speed of 50.0 m/s. What must the tension of the string be?

A long piece of piano wire of radius 0.4 mm is made of steel of density 7.8 X 103 kg/m3 The wire is under a tension of 1.0 X 103 N. What is the speed of transverse waves on this wire? What is the wavelength of a wave on this wire if its frequency is 262 Hz?

SOLUTION: Consider a 1-m-long piece of this wire. The volume of this piece is p X (0.4 X 10-3 m)2 X 1 m = 5.0 X 10-7 m3 and the mass is 5.0 X 10-7 m3 X 7.8 X 103 kg/m3 = 3.9 X 10-3 kg. Hence, the mass per unit length of the wire is 3.9 X 10-3 kg/m. From Eq. (19), the wave speed is then

Consequently, the wavelength is

http://www.lakeheadschools.ca/scvi_staff/childs/Gr11_physics_web/downloadable_content/unit8/Text8/phys11_8_4.pdf