Question

Lake Erie is prone to remarkable seiches-standing waves that slosh water back and forth in the lake basin from the west end at Toledo to the east end at Buffalo. (Figure 1) shows smoothed data for the displacement from normal water levels along The lake at the high point of one particular seiches. 3 hours later the water was at normal levels throughout the basin; 6 hours later the water was high in Toledo and low in Buffalo. What is the frequency? Express your answer to two significant figures and include the appropriate units.

Answer 1

lambda =2L = 2*400 = 800 km

time from toldedo to zero = 3h

this is 1/4 of wavelenght

total time = 12h

f = 1/T

T = 12h = 43200s

f = 2.3 x 10^-5 Hz