# Homework Help: Grade 11 Physics: WAVES. Finding Wavelength & Frequency

1. Sep 27, 2011

### asweetland

I missed the day where we were taught the formulas for frequency & wavelength, so doing the questions below are a struggle. Please someone explain how .

Question 1 (wavelength) : The speed of sound in air at room temperature is 343m/s. The sound wave produced by striking middle C on a piano has a frequency of 256 Hz.
A) Calculate the wavelength of this sound
B) Calculate the wavelength for the sound produced by high C, one octave higher than middle C, with a frequency of 512 Hz.

^ This one I had no idea how to even start. :\$

Question 2 (frequency) : A child swings back and forth on a swing 12 times in 30.0 seconds. Determine the frequency and period of the swinging.
^ This one I did the answer as f/t = 12/30 = .4 so is 0.4 Hz correct?

2. Sep 27, 2011

### iceblits

Question one: you know that velocity of the wave=frequency*Wavelength...that should help you get the wavelength I think.
Question two: I think you did that right..dont forget you also need to calculate the period for that. Remember period=1/frequency