When a musician strums a guitar, the vibration of the strings creates sound waves that human ears hear as music. When a guitar string is plucked, it moves a certain distance, depending on how hard the ...

A frequency shift experienced by an observer whenever a source of waves moves away from or towards the observer is a feature common to all waves — a phenomenon called the Doppler effect. Indeed, ...

Regular oscillation, for instance, by a particle in a solid, fluid or gas, displaced from its normal position or random motion, when the force required is proportional to the displacement. This motion ...