1. Measuring Waves Physics 7(B)

2. Learning Objectives Describe and measure the parts of a wave Explain the relationship between frequency and wavelength Use the wave velocity equation to calculate velocity, frequency, and wavelength Measuring Waves

3. Crest – point of maximum displacement in the positive direction Trough – point of maximum displacement in the negative direction Equilibrium – rest point of a wave Amplitude – maximum displacement of a wave measured from equilibrium to a crest or trough Parts of a Wave

4. Wavelength ( λ ) – distance between two identical points on adjacent waves measuring the length of one full oscillation of a wave – Measured in meters, m Frequency (f ) – number of times that a distinct part of a wave passes a given point in one second – Measured in Hertz, Hz Measuring Waves

5. Frequency and Wavelength For a wave moving with a constant velocity, frequency and wavelength are inversely related – If frequency decreases, wavelength increases – If frequency increases, wavelength decreases

6. Wave velocity (v ) – a measurement of how fast a wave is moving – Dependent on the frequency ( f ) and wavelength ( λ ) of the wave – Measured in meters per second, m/s Frequency measured in hertz Wavelength measured in meters Wave Velocity

7. 3.Convert units and find intermediates, if needed 4.Plug in and solve 5.Make sure the answer is reasonable 1.Write unknowns and givens 1.Identify the formula and rearrange, if needed Ex) A 220 Hz wave has a wavelength of 0.50 m. What is the velocity of the wave? Wave Velocity Calculation

8. Ex) A radio wave has a frequency of 101.5 MHz and travels at the speed of light, 3.00 × 10 8 m/s. Find the wavelength of this radio wave. 3.Convert units and find intermediates, if needed 4.Plug in and solve 5.Make sure the answer is reasonable Wavelength Calculation 1. Write unknowns and givens 2.Identify the formula and rearrange, if needed

9. 3.Convert units and find intermediates, if needed 4.Plug in and solve 5.Make sure the answer is reasonable Ex) A tuning fork vibrates and produces a sound that travels at 343 m/s. If the wavelength of this wave is 0.78 m, what is the frequency of the note that is heard? Frequency Calculation 1.Write unknowns and givens 2.Identify the formula and rearrange, if needed

10. Learning Objectives Describe and measure the parts of a wave Explain the relationship between frequency and wavelength Use the wave velocity equation to calculate velocity, frequency, and wavelength Measuring Waves