Simple Harmonic Motion, Waves, and Sound Flashcards

Vocabulary flashcards defining key physics concepts, formulas, and phenomena related to simple harmonic motion, mass-spring systems, pendulums, waves, sound intensity, the Doppler effect, and resonance.

Restoring Force

A force that acts to maintain equilibrium in a system by pushing it back toward equilibrium.

Simple Harmonic Motion

Oscillatory motion in which a restoring force is directly proportional to the displacement from equilibrium.

Amplitude of Oscillation

The maximum displacement from equilibrium, measured in meters for a mass-spring system or in degrees (symbolized by $\theta$) for a pendulum.

Mass-Spring System Restoring Force

In a horizontal mass-spring system, the restoring force is due to the force in the spring, acting in the direction opposite to displacement.

Kinetic Energy in a Mass-Spring System

Energy of motion that reaches a maximum at the equilibrium position and is zero at maximum displacement.

Elastic Potential Energy in a Mass-Spring System

Stored spring energy that reaches a maximum at maximum displacement and is zero at the equilibrium position.

Pendulum Restoring Force

The force that acts to push a pendulum back toward equilibrium, which is due to the force of gravity.

Period of a Pendulum ($T$)

The time it takes for a pendulum to oscillate back-and-forth once, measured in seconds; depends on length ($L$) and acceleration due to gravity ($g$), but is independent of mass and amplitude.

Period ($T$)

The time it takes for a system to oscillate back-and-forth once, measured in seconds.

Frequency ($f$)

The number of times a system oscillates back-and-forth in one second, measured in hertz ($Hz$).

Spring Constant ($k$)

A measure of the stiffness of a spring, represented by variable $k$ with the unit $N/m$.

Mechanical Wave

A wave that requires a physical medium (such as water, air, rope, or Earth) to travel, transmitting energy rather than matter.

Transverse Wave

A wave in which the particles of the medium move perpendicular to the direction of wave travel.

Longitudinal Wave

A wave in which the particles of the medium move parallel to the direction of wave travel.

Crest

The highest point above equilibrium in a transverse wave.

Trough

The lowest point below equilibrium in a transverse wave.

Compression Region

A region of higher-than-average density in a longitudinal wave.

Rarefaction Region

A region of lower-than-average density in a longitudinal wave.

Wave Energy and Amplitude Relationship

The principle stating that the energy carried by a mechanical wave is proportional to the square of the wave's amplitude.

Fixed Boundary Reflection

A boundary condition where the end of the medium must remain in one place, causing reflected waves to be inverted.

Free Boundary Reflection

A boundary condition where the end of the medium can move up and down, causing reflected waves to remain upright.

Constructive Interference

Wave interference that occurs when waves have an additive effect, combining their amplitudes.

Destructive Interference

Wave interference that occurs when waves have a subtractive effect, causing their amplitudes to cancel each other out.

Wave Speed ($v$)

The speed at which a wave travels, measured in meters per second ($m/s$), which depends solely on the properties of the medium.

Wavelength ($\lambda$)

The distance between repeating units of a wave, represented by the variable $\lambda$ and measured in meters ($m$).

Standing Wave

An unchanging wave pattern produced when incident and reflected waves interfere both constructively and destructively.

Node

A point along a standing wave that remains motionless and has zero amplitude.

Antinode

A point along a standing wave that undergoes maximum positive to maximum negative displacement, reaching maximum amplitude.

Closed Tube

A tube open at one end and closed at the other, forming nodes at closed ends and antinodes at open ends, with only odd harmonics present.

Open Tube

A tube open at both ends, forming antinodes at both open ends, with both odd and even harmonics present.

Infrasonic Waves

Sound waves with frequencies below $20\,Hz$.

Ultrasonic Waves

Sound waves with frequencies above $20,000\,Hz$.

Fundamental Frequency

The lowest primary frequency produced by a sound source, which determines its pitch.

Timbre

The unique sound quality of a voice or instrument, determined by which harmonics are present and the intensity of each harmonic.

Doppler Effect

An observed change in frequency resulting from relative motion between a wave source and an observer.

Subsonic Speed

Speed that is slower than the speed of sound.

Supersonic Speed

Speed that is faster than the speed of sound.

Bow Wave

A two-dimensional V-shaped wave barrier created when a source moves faster than the speed of surface water waves.

Shock Wave

A three-dimensional cone-shaped wave formed when an object travels faster than the speed of sound.

Sonic Boom

A loud sound caused by high-pressure air produced by an object moving faster than the speed of sound.

Sound Intensity

Power per unit area given by $I = \frac{P}{4\pi R^2}$, measured in watts per square meter ($W/m^2$).

Beats

Variations in loudness produced by interference between two sound frequencies that are close but not identical.

Beat Frequency

The rate of loudness variation, calculated as the absolute value of the difference between two close sound frequencies.

Natural Frequency

The specific frequency at which an object most easily vibrates or oscillates.

Resonance

A phenomenon occurring when a force is repeatedly applied to an object at its natural frequency, resulting in large vibration amplitudes.

Aeolian Harp

A wire that resonates and hums because of the wind brushing against it at its natural frequency.