To fully understand the various acoustical aspects of sound production, it is generally necessary to use powerful mathematical methods such as calculus. However, it is possible to understand a great deal about the physical aspects of sound production with just a few simple concepts.
The mass of an object is a measure of its opposition to acceleration.
Mass and weight are often confused. Weight is the force of gravity on an object. Gravity causes objects to free fall with a constant acceleration (9.8 meters/second on earth). An object's weight will vary depending on a given gravity. An object will have the exact same mass, however, for any gravity.
Force is typically measured in Newtons (kg meters/second).
Pressure is defined as the force acting perpendicular to a surface divided by the area of that surface:
Pressure is a particularly useful quantity to consider when dealing with fluids (liquids and gases), such as air.
Work is done when force is applied to an object that moves.
Work is typically measured in newton-meters, or joules.
Energy comes in many forms though we will mainly be concerned with kinetic (energy of motion) and potential (stored) energy in this course.
An object of mass moving with a velocity has kinetic energy given by
The same object held at a distance above the floor has potential energy given by
, where is the acceleration of gravity.
If the object then falls to the ground, the work done by gravity would also equal . As the object falls, potential energy is converted to kinetic energy. The object's final velocity just before hitting the floor can be determine by equating gain of KE to loss of PE: