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Problem 5. We are interested in comparing the viscosity of different ketchups. We can measure the shear stress as a function of shear rate by placing ketchup in a sliding plate rheometer. If you pull on the top plate at a constant velocity v and keep the bottom plate fixed, a velocity gradient will form. We measure the resulting force required to pull the plate. We can convert those forces into stress ($\tau = F/A$) and plot the data for a range of shear rates ($\gamma' = dv/dh$). a) (3 pt.) What is the viscosity of the Heinz ketchup? Approximate using the data in the stress vs. shear rate plot below. b) (3 pt.) What is the viscosity of the Kroger brand ketchup? Approximate using the data in the stress vs. shear rate plot below. c) (4 pt.) Is ketchup a Newtonian fluid, a non-Newtonian fluid, or a Bingham fluid according to the data? Compare the flow behavior of the two ketchups. Which is easier to get out of the bottle and why? Be as quantitative as possible in your answer. Shear Stress (Pa) Shear Rate (1/s) Heinz Kroger Moving wall v Fixed bottom plate

          Problem 5. We are interested in comparing the viscosity of different ketchups. We can measure the shear stress as a function of shear rate by placing ketchup in a sliding plate rheometer. If you pull on the top plate at a constant velocity v and keep the bottom plate fixed, a velocity gradient will form. We measure the resulting force required to pull the plate. We can convert those forces into stress ($\tau = F/A$) and plot the data for a range of shear rates ($\gamma' = dv/dh$).

a) (3 pt.) What is the viscosity of the Heinz ketchup? Approximate using the data in the stress vs. shear rate plot below.
b) (3 pt.) What is the viscosity of the Kroger brand ketchup? Approximate using the data in the stress vs. shear rate plot below.
c) (4 pt.) Is ketchup a Newtonian fluid, a non-Newtonian fluid, or a Bingham fluid according to the data? Compare the flow behavior of the two ketchups. Which is easier to get out of the bottle and why? Be as quantitative as possible in your answer.

Shear Stress (Pa)
Shear Rate (1/s)
Heinz
Kroger
Moving wall v
Fixed bottom plate

problem 5 we are interested in comparing the viscosity of different ketchups we can measure the shear stress as a function of shear rate by placing ketchup in a sliding plate rheometer if yo 54066

Added by Angela W.

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