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#glycerine film

2 public questions tagged with this topic.

Equation of Continuity and Flow Rate

A plate of area 0.08m2 moves at 0.8m/s over a 0.7mm thick glycerine film (η\=0.83Pa s). What force is required?

Viscous force: F = ηvAl. η = 0.83Pa s, v = 0.8m/s, A = 0.08m2, l = 0.7×10−3m. F = 0.83×0.8×0.080.7×10−3 = 0.83×91.43 = 75.89N. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 76 N. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.

Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.

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Fluid Pressure, Pascal's Law and Manometers

A plate of area 0.06m2 moves at 0.6m/s over a 0.4mm thick glycerine film (η\=0.83Pa s). What force is required?

Viscous force: F = ηvAl. η = 0.83Pa s, v = 0.6m/s, A = 0.06m2, l = 0.4×10−3m. F = 0.83×0.6×0.060.4×10−3 = 0.83×90 = 74.7N. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 74.7 N. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.

Ref: NCERT Class 11 Physics, Thermal Properties and Gravitation.

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