1.10. Example Problems on Shear Stress and Terminal Velocity

Try these first

1. 1.

   Define shear stress in your own words.

   Hint

   Remember the relationship between force and area.

2. 2.

   What is terminal velocity?

   Hint

   Think of falling objects reaching a steady speed.

3. 3.

   What is the unit of shear stress?

   • Pa
   • N/m²
   • kg/m·s²

   Hint

   Think about how we define pressure.

4. 4.

   Terminal velocity occurs when:

   • True
   • False

   Hint

   Remember the forces acting on a falling body.

5. 5.

   A raindrop falls through air and reaches terminal velocity of 9 m/s. If the mass of the drop is 0.002 kg, calculate the drag force acting on it.

   Hint

   Use the weight formula.

6. 6.

   A viscous fluid flows between two parallel plates with a 5 mm gap. If one plate moves at 0.1 m/s and shear stress is measured at 200 Pa, calculate the dynamic viscosity.

   Hint

   Consider the height difference to derive du/dy.