PHYS 256 Musical Acoustics Syllabus rses/phys256/phys256home.html

Textbook The Physics of Sound, 3/E Richard E Berg David G Stork Richard E. Berg: B.S, M.S, Ph.D; Professor of Physics, University of Maryland. B.S in Music with emphasis on piano and clarinet. David G. Stork: B.S, M.S, PhD; Chief Scientist, Ricoh Innovations, Inc. Accomplished orchestral and chamber timpanist/percussionist.

Instructor Ponn Maheswaranathan: B.S, M.S, PhD; Professor of Physics, Winthrop Native of Sri Lanka, Naturalized U.S. citizen

Fundamental Definitions 1.Position, Length, Distance 2.Time 3.Velocity or Speed 4.Acceleration 5.Mass 6.Density 7.Force 8.Pressure

Position, Length, Distance 1.Cartesian Coordinate System (x and y) 2.Prefixes 3.Metric System

Time 1.Time interval can be measured using the following units: second, minute, hour, day, month, year, etc. 2.The following smaller units are also used: millisecond (ms), microsecond (µs). 3.Calculate the period (T) of a 440 Hz tone.

Speed and Velocity Speed = Distance/Time Velocity = Speed + Direction. Speed of sound in air = 345 m/s = 1100 ft/s Speed of light = 3x10 8 m/s = 186,000 miles/s.

Acceleration Acceleration is the rate at which velocity changes. Units: m/s 2, cm/s 2 Acceleration due to gravity = g = 9.8 m/s 2.

Mass Mass is a measure of the amount of matter contained in an object.

Examples of Mass A massive supertanker, for instance, is one that contains an enormous amount of mass. In comparison, a penny does not contain much mass. Mass is a scalar quantity.

Mass Density The mass density  is the mass m of a substance divided by its volume V: SI Unit of Mass Density: kg/m 3

Linear and areal Density Linear density of stretched wires is important in the design of stringed instruments. Linear Density = Mass per unit length. Areal Density = Mass per unit area.

Force In common usage, a force is a push or a pull. Forces can be categorized as, Contact forces and Non-Contact forces.

Newton's Second Law of Motion Newton’s second law is a relationship between acceleration, forces, and mass. When a net external force acts on an object of mass m, the acceleration a that results is directly proportional to the net force and has a magnitude that is inversely proportional to the mass. The direction of the acceleration is the same as the direction of the net force. SI Unit of Force: : kg · m/s 2 = newton (N)

Weight Weight is the force of gravity. Weight = Mass x Acceleration due to gravity. On the moon, your weight will be 1/6 th of that of Earth weight, because the acceleration due to gravity is 1/6 th of that of Earth’s.

Units QuantitySI unitVector or Scalar

Pressure People who have fixed a flat tire know something about pressure. In colliding with the inner walls of the tire, the air molecules (blue dots) exert a force on every part of the wall surface.

Pressure The pressure P exerted by a fluid is defined as the magnitude F of the force acting perpendicular to a surface divided by the area A over which the force acts: The SI unit for pressure: newton/meter 2 = (N/m 2 ) = pascal (Pa).

Pressure Illustration

Human Ear Rapid changes in air pressure cause vibrations of the eardrum, which we hear as sound.