Which of the following statement is wrong?

Options

A. The moment of linear momentum is a vector quantity
B. The moment of the mass is called moment of inertia
C. The moment of linear momentum is called angular momentum
D. The moment of a force is called torque.

Answer

To determine which statement is wrong among the given options, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Analyze Statement 1**: "The moment of linear momentum is a vector quantity."
- Linear momentum (p) is defined as the product of mass (m) and velocity (v), i.e., \( p = mv \).
- The moment of linear momentum refers to angular momentum (L), which is given by the cross product of the position vector (r) and linear momentum (p), i.e., \( L = r \times p \).
- Since both r and p are vector quantities, their cross product (angular momentum) is also a vector quantity.
- **Conclusion**: This statement is **correct**.

2. **Analyze Statement 2**: "The moment of mass is called moment of inertia."
- Moment of inertia (I) is defined as \( I = \sum m_i r_i^2 \), where \( r_i \) is the distance from the axis of rotation.
- The term "moment of mass" is not a standard term in physics. The moment of inertia is related to the mass distribution relative to an axis, but it is not simply the "moment of mass."
- **Conclusion**: This statement is **incorrect**.

3. **Analyze Statement 3**: "The moment of linear momentum is called angular momentum."
- As previously discussed, angular momentum is indeed the moment of linear momentum, defined as \( L = r \times p \).
- **Conclusion**: This statement is **correct**.

4. **Analyze Statement 4**: "The moment of a force is called torque."
- Torque (τ) is defined as the cross product of the position vector (r) and force (F), i.e., \( τ = r \times F \).
- Thus, the moment of a force is indeed referred to as torque.
- **Conclusion**: This statement is **correct**.

### Final Conclusion:
The only statement that is incorrect is **Statement 2**: "The moment of mass is called moment of inertia."