Water waves crash in on the beach at a velocity of 3.5 m s . if the distance between the crest of each wave is 4 m, determine the frequency of the water waves. v = fλ.

a) 0.88 hz
b) 7.0 hz
c) 14.0 hz

so here is the information for current research:

-nrel's geothermal analysts, scientists, and engineers perform a full range of research from developing advanced methods of locating and accessing geothermal resources to exploring innovative technologies to extract and produce clean energy from the heat of the earth

and here is the information for the technology of geothermal energy:

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