Wave Speed

• Calculating Wave Speed
  
  
  To calculate wave speed you need to know two measurements:
  
  1. Wavelength
  2. Frequency
  

Wave Speed

v

f

λ

• You can do algebra magic and make two more equations out of the wave speed formula.

• Sometimes, it is easier to just use the triangle method instead of algebra.

Equation Triangle

​

• Use the triangle to rearrange the wave speed equation.

  1. Cover the unit you need to calculate.

  2. The horizontal line represents division.

  3. The vertical line represents multiplication

Multiple Choice

The vertical line means

• addition

• subtraction

• multiplication

• division

Multiple Choice

The horizontal line means

• addition

• subtraction

• multiplication

• division

Multiple Choice

Frequency =

• Wave speed * Wavelength

• Wave speed / Wavelength

• Wave speed + Wavelength

• Wave speed - Wavelength

Multiple Choice

Wavelength =

• Wavespeed * Frequency

• Wavespeed / Frequency

• Frequency * Wavespeed

• Frequency/wave speed

Multiple Choice

Wave speed =

• Wavelength * Frequency

• Wavelength / Frequency

• Wavelength + Frequency

• Wavelength - Frequency

Multiple Choice

A wave has frequency of 50 Hz and a wavelength of 10 m. What is the speed of the wave?

• 500 m/s

• 50 m/s

• 5 m/s

• 0.5 m/s

Refer to this lesson/review/guide at any time while completing the handout activity.

Multiple Choice

A wave has frequency of 5 Hz and a speed of 25 m/s. What is the wavelength of the wave?

• 25 m

• 125 m

• 5 m

• 25 m/s

Multiple Choice

What is the frequency of a wave traveling at 300 m/s with a 4 m wavelength?

• 0.013 Hz

• 75 Hz

• 300 Hz

• 1200 Hz

Draw

What is the speed of a sound wave that has
a wavelength of 2 m and a frequency of
170.5 Hz?

341 m/s

Draw

A wave traveling in water has a frequency of 500 Hz and a wavelength of 3 m. What is the speed of the wave?

1,500 m/s

Draw

The lowest-pitched sounds humans can hear have a frequency of 20 Hz. What is the wavelength of these sound waves if their wave speed is 340 m/s?

17 m

Draw

Calculate the frequency of a water wave that has a wavelength of 0.5 m and a speed of 4 m/s.

20,000 Hz

Draw

The highest-pitched sound humans can hear have a wavelength of 0.017 m in air. What is the frequency of these sound waves is their wave speed is 340 m/s?

8 Hz

Draw

An FM radio station broadcasts radio waves with a frequency of 100,000,000 Hz. What is the wavelength of these radio waves if they travel at a speed of 300,000 km/s?

0.003 km