Ch 16: Waves & SoundWorksheetSee all chapters
All Chapters
Ch 01: Units & Vectors
Ch 02: 1D Motion (Kinematics)
Ch 03: 2D Motion (Projectile Motion)
Ch 04: Intro to Forces (Dynamics)
Ch 05: Friction, Inclines, Systems
Ch 06: Centripetal Forces & Gravitation
Ch 07: Work & Energy
Ch 08: Conservation of Energy
Ch 09: Momentum & Impulse
Ch 10: Rotational Kinematics
Ch 11: Rotational Inertia & Energy
Ch 12: Torque & Rotational Dynamics
Ch 13: Rotational Equilibrium
Ch 14: Angular Momentum
Ch 15: Periodic Motion (NEW)
Ch 15: Periodic Motion (Oscillations)
Ch 16: Waves & Sound
Ch 17: Fluid Mechanics
Ch 18: Heat and Temperature
Ch 19: Kinetic Theory of Ideal Gasses
Ch 20: The First Law of Thermodynamics
Ch 21: The Second Law of Thermodynamics
Ch 22: Electric Force & Field; Gauss' Law
Ch 23: Electric Potential
Ch 24: Capacitors & Dielectrics
Ch 25: Resistors & DC Circuits
Ch 26: Magnetic Fields and Forces
Ch 27: Sources of Magnetic Field
Ch 28: Induction and Inductance
Ch 29: Alternating Current
Ch 30: Electromagnetic Waves
Ch 31: Geometric Optics
Ch 32: Wave Optics
Ch 34: Special Relativity
Ch 35: Particle-Wave Duality
Ch 36: Atomic Structure
Ch 37: Nuclear Physics
Ch 38: Quantum Mechanics
What is a Wave?
The Mathematical Description of a Wave
Waves on a String
Wave Interference
Standing Waves
Sound Waves
Standing Sound Waves
Sound Intensity
The Doppler Effect

Concept #1: Sound Intensity

Practice: A source emits a sound in the shape of a cone, as shown in the figure below. If you measure the intensity to be 100 W/m2 at a distance of 0.5 m, what is the power of the source?

Concept #2: Volume And Intensity Level

Practice: A source emits sound spherically with a power of 2.2 × 104 W. What is the minimum distance away from this sound that would be considered safe (a volume of 150 dB or less)?

Additional Problems
A human can only hear sound above I 0 = 10 -12 W/m2, called the threashold of hearing. If a 100 W speaker emits sound at 500 Hz, what is the furthest distance from the source you could stand and still hear the sound emitted? What would be the furthest distance if the speaker's tune was changed, and now emits a sound at 100 Hz?
Sound is emitted from a 100 W source at a 50 Hz. From a distance of 10 m, what is the maximum pressure produced by the compression of air from the sound waves? Consider the density of air to be 1.225 kg/m3 and the speed of sound to be 340 m/s.
Standing 15 m from a speaker, the speaker has a volume of 40 dB. What's the furthest distance from the speaker you would still be able to hear it from? A) 150 m B) 1,500 m C) 15,000 m D) 150,000 m
By how many decibels does the intensity level of a sound increase when you triple the intensity of a source of sound? A) 9.5 dB B) 4.8 dB C) 6.0 dB D) 3.0 dB E) 12 dB
Standing 1 m from a speaker, you hear a sound of 50 dB. What would the volume of the sound be if you were to walk 9 m away from the speaker?A) 30 dBB) 40 dB C) 60 dBD) 70 dB
A speaker is emitting energy in the form of sound, at a rate of 200 J every second. If you were 15 m from the speaker, and your ear was pointing directly to the speaker (so sound waves enter directly into your ear canal), how much "sound-energy" (energy in the form of sound) enters your ear canal per second? Assume your ear canal is cylindrical with a diameter of 0.7 cm.
The intensity level for busy traffic is β1 = 81 dB. Two people having a loud conversation have an intensity level of β2 = 70 dB. What is the combined intensity level?
The intensity of the waves from a point source at a distance  d from the source is I. At what distance from the sources is the intensity equal to 2I?A) d/2B) d/√2C) d/4D) d/8
The sound intensity is 0.0080 W/m2 at a distance of 10 m from an isotropic (same intensity in all directions) point source of sound.(a) What is the power of the source?(b) What is the sound intensity 5.0 m from the source?(c) What is the sound level 10 m from the source? The threshold of human hearing is I0 = 1.0 × 10 -12 W/m2 .
A sound system emits 100 W of power from a speaker. At 10 m away the intensity is I. How far from the source must you be for the intensity to be cut in half? A. The intensity remains constant B. 10√2 m C. 20 m D. 40 m
By what amount does the intensity level increase when you triple the intensity of a source of sound? (Hint: subtract the old from the new!) a) 9.5 dB b) 4.8 dB c) 6.0 dB d) 3.0 dB e) 12 dB