A fish in water (μ=4/3) rises at 2 cm/s while a bird in air descends at 4 cm/s. The interface is stationary. At what rate does the apparent separation decrease as measured by the bird?
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A fish in water (μ=4/3) rises at 2 cm/s while a bird in air descends at 4 cm/s. The interface is stationary. At what rate does the apparent separation decrease as measured by the bird?

G1 Physics · Accepted Answer

Fish appears to rise at 2/(4/3)=1.50; closing speed=5.50 cm/s.