A bat emits a sound wave with a frequency of 25.0 kHz and a wavelength of 0.0136 metres. Calculate the speed of this sound wave.

In this question you are given frequency and wavelength of the wave and you are asked for the speed. You need to use the formula on you sheet that uses these three properties : v = f x λ, where v is the speed, f is the frequency and λ is the wavelength.

You know from the question that f = 25kHz and λ = 0.0136m, however 1 kHz is actually 1000 Hz and you need to remember this before you do your calculation. Therefore the numbers you need to put into your calculator are f = 25 x 1000 = 25000 and λ = 0.0136.

The calculation that you then need to do is 25000 x 0.0136 = 340. You must not forget the units of speed, which here are metres per second, or m/s. Your final answer is 340 m/s.