SHM & Waves

Repetitive Motion

Force is proportional to the displacement.

Cycle

Unit of motion that repeats.

Amplitude

Maximum displacement from the equilibrium point, bigger the amplitude bigger the cycle.

Period, T (seconds)

The time to do one cycle.

Frequency, f (Hertz)

How many cycles happen in 1 second.

Formula for Period (T)

Seconds / cycle

Formula for Frequency (F)

Cycles / second

Wave

Oscillating disturbance that travels, carries energy from one place to place but particles on oscillate around a fixed position.

Wavelength

How long a wave is, length of one cycle of the wave that repeats.

Parts of a Wave

Amplitude and wavelength.

Transverse Wave

Wave that oscillates perpendicular to the direction the wave moves.

Longitudinal Waves

Wave that oscillates in the same direction as the wave moves.

Formula for Speed of a Wave

Wavelength * frequency.

Reflection

Wave bounces off a material and goes in a new direction.

Refraction

Wave passes through a material and bends.

Diffraction

Wave bends around or goes through a hole in a material. When plane waves go through a small hole, they become circular waves.

Absorption

Wave is absorbed by a material and may disappear.

Constructive Interference

Two waves add up to create a larger amplitude.

Destructive Interference

Waves add up to make a smaller amplitude.

Fundamental Wave

The standing wave with the longest wavelength

Harmonics

All other wavelengths.

Doppler Effect

Occurs when a sound source is moving at speeds less than the speed of sound. Sounds go to higher pitch when moving towards each other and lower pitch when moving away.

The Speed of Sound

343 meters per second

Subsonic

When an object moves slower than sound.

Supersonic

To describe motion at speeds faster than the speed of sound.

Shock Wave

Forms where the wave fronts pile up.

Sonic Boom

The pressure change across the shock wave is what causes a very loud sound.

Consonance

Frequencies far enough apart where there are no beats.

Dissonance

Frequencies are too close together, there are beats.

Beats

Occur when two frequencies are close, but not exactly the same.