Waves And Wave Properties Applied Physics and Chemistry

Waves And Wave Properties Applied Physics and Chemistry SHM Lecture 2

Wave A disturbance that transmits energy Mechanical waves: require a medium to move Transverse waves Longitudinal waves

Transverse Wave Movement perpendicular to direction of wave Example: light

Longitudinal Wave Movement parallel to direction of wave Series of compressions and rarefactions Example: sound

Measuring the Wave Speed: depends on the medium Measured in m/s Amplitude: maximum displacement from rest Wavelength: distance between points where wave pattern repeats Frequency: number of waves that pass a point in one second Measured in Hertz (Hz): 1 Hz is one wave/second

Wave Equation Relates frequency, velocity and wavelength V=fλ There is also a relationship between period and frequency T = 1/f

Sample Problem A sound wave has a frequency of 192 Hz and travels the length of a football field (91. 4 m) in 0. 271 s. What is the speed of the wave? Known: f=192 Hz d=91. 4 m t=0. 271 s Equation: V=d/t (no known λ) Solve: V=(91. 4 m)/(0. 271 s) = 337 m/s

Sample Problem Continued Find the wavelength of the wave. Known: V=337 m/s f=192 Hz Equation V=fλ so λ=V/f Solve: λ=(337 m/s)/192 Hz So λ= 1. 76 m

Sample Problem Continued What is the period of the wave? Known: f=192 Hz Equation: T=1/f Solve: T=1/192 Hz T=0. 00521 s

Sample Problem Continued If the frequency was changed to 442 Hz, what would the new wavelength be? Known: V=337 m/s f=442 Hz Equation: V=fλ so λ=V/f Solve: λ=(337 m/s)/(442 Hz) And λ=0. 762 m

Now you try it! Solve the problems on your worksheet! Remember the wave equation and the relationship between period and frequency.