1. The problem statement, all variables and given/known data
The block of ice (temperature 0°C) shown in Figure P9.57 is drawn over a level surface lubricated by a layer of water 0.10 mm thick. Determine the magnitude of the force needed to pull the block with a constant speed of 0.50 m/s. At 0°C, the viscosity of water has the value η = 1.79 × 10^–3 N ∙ s / m^2.
I have attached the image. The surface is 0.80 x 1.20m, with force pointing to the right.
2. Relevant equations
Force = Pressure x Area
m = pV, p = 1.00 x 10^3 kg/m^3
not sure how these are helpful.
3. The attempt at a solution
Can I just multiply the viscosity by the speed by the area of the surface divided by the thickness of the water to get the force?
So F= ηv x A / thickness = 1.79 x 10^-3 Ns/m^2 x 0.5 m/s x 0.8 x 1.2 m /0.10 = 8.6 x 10^-2 N?
The units cancel out.. not sure if this is the right approach though. I don't really know where to begin. Can anyone please help / guide me?
EDIT: Sorry... it accidentally posted when I couldn't complete the subject title. I would want it entitled "Basic Question about Force for Fluid Mechanics
The block of ice (temperature 0°C) shown in Figure P9.57 is drawn over a level surface lubricated by a layer of water 0.10 mm thick. Determine the magnitude of the force needed to pull the block with a constant speed of 0.50 m/s. At 0°C, the viscosity of water has the value η = 1.79 × 10^–3 N ∙ s / m^2.
I have attached the image. The surface is 0.80 x 1.20m, with force pointing to the right.
2. Relevant equations
Force = Pressure x Area
m = pV, p = 1.00 x 10^3 kg/m^3
not sure how these are helpful.
3. The attempt at a solution
Can I just multiply the viscosity by the speed by the area of the surface divided by the thickness of the water to get the force?
So F= ηv x A / thickness = 1.79 x 10^-3 Ns/m^2 x 0.5 m/s x 0.8 x 1.2 m /0.10 = 8.6 x 10^-2 N?
The units cancel out.. not sure if this is the right approach though. I don't really know where to begin. Can anyone please help / guide me?
EDIT: Sorry... it accidentally posted when I couldn't complete the subject title. I would want it entitled "Basic Question about Force for Fluid Mechanics
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