Question

A rubber ducky floats in a bath tub. How many times per minute does it bob up and down in bath waves that have a wavelength of 0.21 m and propagation speed of 4.2 m/s? (Remember it's per minute! And round your answer down to the near whole number, the question is asking to count the number of bobs up and down. Counting goes 1...2..3.. etc. No decimals!)

Answer 1

given
wavelength, lamda = 0.21 m
wave speed, v = 4.2 m/s

let f is the frequency

we know, v = lamda*f

==> f = v/lamda

= 4.2/0.21

= 20 Hz

so, makes 20 oscillations in one second

in one minute it makes 120 oscillations.

120 <<<<<<<---------Answer