Question

Chapter 20 Sound Be able to define compression and rarefaction. Be able to explain the concepts of forced vibration, natural frequency, and resonance. Be able to apply the concepts of forced vibration, natural frequency, and resonance. • Be able to explain and apply the concept of beats.

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Answer 1

1. Compression is a region in a longitudinal wave where the particles are closest to each other.

A rarefaction is a region in a longitudinal wave where the particles are distant.

In a sound wave, the region where the medium is compressed is known as compression and the region where the medium is spread out is known as a rarefaction.

2&3. Forced vibration is a type of vibration in which a force is repeatedly applied to a mechanical system. Forced vibration is when an alternating force or motion is applied to a mechanical system, for example when a washing machine shakes due to an imbalance.

Natural frequency is the frequency at which a system tends to oscillate in the absence of any driving or damping force. The motion pattern of a system oscillating at its natural frequency is called the normal mode.

Resonance increases in the amplitude of oscillation of an electric or mechanical system exposed to a periodic force whose frequency is equal or very close to the natural undamped frequency of the system. two vibrating systems having the same frequency are in resonance. Mathematically it is given as $f_{1} = f_{2}$

Beat: When two objects vibrate with different frequencies, you hear a fluctuating sound (soft and loud sound alternatively). ... When two sound waves of slightly different frequencies approach your ear, you hear a fluctuating sound (soft and loud sound alternatively). This phenomenon is known as beats.

Beats in physics occur when two waves of nearby frequencies overlap. Ex: in musical instrument