Aeroplanes are streamlined to reduce

Options

A. fluid friction
B. sliding friction
C. kinetic friction
D. limiting friction

Answer

To solve the question "Aeroplanes are streamlined to reduce," we need to analyze the reasons behind the design of aeroplanes and the type of friction they encounter while flying.

### Step-by-Step Solution:

1. **Understanding Streamlining**:
- Streamlining refers to the design of an object that allows it to move through a fluid (like air) with minimal resistance. This design helps in reducing turbulence and drag.

2. **Identifying the Fluid**:
- In the context of aeroplanes, the fluid is air. Air is considered a fluid because it can flow and has the ability to exert forces on objects moving through it.

3. **Types of Friction**:
- When an aeroplane moves through the air, it experiences friction. The relevant types of friction in this scenario are:
- **Fluid Friction**: This is the resistance experienced by an object moving through a fluid. It is the primary type of friction that affects aeroplanes.
- Other types of friction mentioned (sliding friction, kinetic friction, limiting friction) are not applicable in the context of aeroplanes flying through air.

4. **Purpose of Streamlining**:
- The main purpose of streamlining an aeroplane is to reduce fluid friction (drag) as it moves through the air. By reducing this friction, the aeroplane can achieve higher speeds and better fuel efficiency.

5. **Conclusion**:
- Therefore, aeroplanes are streamlined to reduce fluid friction. This design helps in minimizing the drag force acting against the motion of the aircraft, allowing for smoother and more efficient flight.

### Final Answer:
Aeroplanes are streamlined to reduce fluid friction.

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