A river flows towards south at 10 km/hr.Wind blowing south at the speed of 30 km/hr gives rise waves on river surface these waves travels at 20 km.hr relative to the water.The waves are observed skindiver,a balloonist in air above the river and a fishman on the bank.What is the ratio of frequencies the three persons observed
2007-01-09 19:29:23 · 1 answers · asked by Ankur 1 in Science & Mathematics ➔ Physics
This is a fun one!
The skin diver, moving with the water, sees the waves travelling at 20 km/hr.
The balloonist, moving with the wind, sees the waves as stationary (wind and waves both travel 20 km/hr south relative to the water).
The fisherman sees the waves travelling at 30 km/hr.
Frequency = wave speed / wavelength; they will all see the same wavelength, so the frequency will be proportional to the observed wave speed.
Hence the ratio skindiver:balloonist:fisherman is 2:0:3.
2007-01-09 19:39:03 · answer #1 · answered by Scarlet Manuka 7 · 1⤊ 0⤋