A wetting liquid rises 6 cm in a capillary tube when the system is stationary. The same apparatus is placed in an elevator accelerating vertically upward at 5 m/s². Take g = 10 m/s². If the new capillary rise is N cm, find N.
Physics · Properties of solid and fluid · properties of fluid and surface tension
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Question

A wetting liquid rises 6 cm in a capillary tube when the system is stationary. The same apparatus is placed in an elevator accelerating vertically upward at 5 m/s². Take g = 10 m/s². If the new capillary rise is N cm, find N.

Physics · Properties of solid and fluid · properties of fluid and surface tension

G1 Physics · Accepted Answer

At rest, h₀ = 6 cm. For upward acceleration, g(eff) = g+a = 15 m/s². Since capillary height is inversely proportional to effective gravity, h = h₀g/(g+a). Therefore, h = 6×10/15 = 4 cm. Hence, N = 4.