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#### Interactive Self-Study Module: Viscosity and Shear Stress

##### Overview:

This module uses screencasts and interactive simulations to relate shear stress and velocity profiles. Screencasts are used to show how viscous fluids create shear stresses. An interactive simulation and example problems allow the user to test themselves. Your retention of material in this module will increase if you write down reasons for your answers to ConcepTests, questions in screencasts, and questions to answer before using interactive simulations, and you try to solve the example problems before watching the screencast solutions. We suggest using the learning resources in the following order:

1. Attempt to answer the multiple-choice before watching the screencasts or working with the simulations.
2. Watch the screencasts that introduce the idea of viscosity and relate shear stress to velocity profile and answer the question in the first screencast.
3. Review important equations for viscosity and shear stress.
4. Use the interactive simulation to understand the effect shear stress has on velocity profiles.
5. Try to solve the example problem before watching the solution in the screencast.
6. Answer the ConcepTests.
7. Look at the list of key points, but only after you try to list the key points yourself.
##### Motivation:
• A fluid is defined as a substance that deforms continuously when a shear stress is applied. An understanding of shear stress and velocity profiles is essential to fully comprehend what a fluid is.
• This module is intended for a fluid dynamics course.
##### Before studying this module, you should be able to:
• Take simple derivatives.
• Explain what tangential forces are.
• Explain the difference between a force and a stress.
##### After studying this module, you should be able to:
• Use the velocity profile to determine the shear stress.
• Distinguish between Newtonian and non-Newtonian fluids.
• Calculate the viscosity of a fluid knowing the shear stress.
• Determine how changing tangential forces and viscosity affects velocity profiles.