Question

Which of the following statements are correct ?
1. Friction and pressure drag depend upon the shape and position of immersed body.
2. If a thin plate is kept parallel to the direction of flow, then the pressure drag is zero.
3.If a thin plate, is kept perpendicular to the moving fluid, then friction drag is zero

• A. 1 and 2 only
• B. 1 and 3 only
• C. 2 and 3 only
• D. 1, 2 and 3

Answer 1

The correct option is D 1, 2 and 3

Friction drag and pressure drag depend on shape and position of immersed body.
When thin plate is held parallel to direction of flow, the projected area is nearly zero as plate is thin so pressure drag is zero and when thin plate is held perpendicular to direction of flow total drag is equal to pressure drag and friction drag is zero