A ripple tank dipper makes 8 water waves in a time of 2s.  When it is just about to make the 9^th wave, the first wave has travelled 48 cm from the dipper.

(a)    What is the frequency of the waves?

(b)   What is the wavelength of the waves?

(c)    What is the wave speed?

(a) Period of each wave = 2/8 = 0.25 s (P) f = 1/0.25 = 4 Hz (P)

(b) wavelength = 48/8 = 6 cm (P)

(c) speed v = fl = 4 Hz  ´ 6 cm = 24 cm/s (P)