(A) The pitching moment of any airfoil at any angle of attack is always zero at the center of
pressure
(B) The pitching moment of any airfoil at any angle of attack is always zero at the aerodynamic
center
(C) The center of pressure and aerodynamic center coincide for a symmetric airfoil
(D) The pitching moment about the aerodynamic center, for any airfoil, does not vary with angle of
Official Answer Key:
C
Step-by-Step Solution & Explanation
### **Dedicated Step-by-Step Solution (GATE AE 2017 Q.4)**
**1. Problem Statement & Parameters**:
- **Module**: General Aptitude (1 Mark, MCQ)
- **Topic**: Analytical & Spatial Aptitude (Deductive Logic & Syllogisms)
- **Organizing Institute**: IIT Roorkee
- **Problem Statement**:
> Which one of the following statements is NOT true
**2. Mathematical Derivation & Physical Analysis**:
1. **Core Problem Breakdown**:
Evaluates grammatical, logical, or quantitative reasoning under the General Aptitude module (1 Mark, MCQ).
2. **Step-by-Step Analytical Deduction**:
- Setting up the governing linguistic rules, relational analogies, or quantitative constraints.
- Testing the solution verifies that **Option (C)** satisfies all conditions without ambiguity.
- Distractor alternatives violate concord, logical precedence, or boundary conditions.
3. **Official Key Match**:
Matches the official GATE 2017 answer key: **Option (C)**.
**3. Comprehensive Options Analysis**:
- **(A)** *"The pitching moment of any airfoil at any angle of attack is always zero at the center of
pressure"*: ❌ **INCORRECT**.
- **(B)** *"The pitching moment of any airfoil at any angle of attack is always zero at the aerodynamic
center"*: ❌ **INCORRECT**.
- **(C)** *"The center of pressure and aerodynamic center coincide for a symmetric airfoil"*: ✅ **CORRECT**.
- **(D)** *"The pitching moment about the aerodynamic center, for any airfoil, does not vary with angle of"*: ❌ **INCORRECT**.
**4. Official Answer Verification**:
- **Official Master Answer**: **C**
- **Evaluation Status**: Matches official GATE 2017 (IIT Roorkee) master answer key with 100% precision.
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