Moment of couple is called

Options

A. angular momentum
B. force
C. torque
D. impulse

Explanation

To solve the question "Moment of couple is called," we will analyze the options provided: angular momentum, force, torque, and impulse.

### Step-by-Step Solution:

1. **Understanding the Concept of a Couple**:
- A couple consists of two equal and opposite forces whose lines of action do not coincide. This creates a rotational effect without any translational movement.

2. **Defining the Moment of a Couple**:
- The moment of a couple is defined as the product of one of the forces and the perpendicular distance between the lines of action of the forces. It is a measure of the rotational effect produced by the couple.

3. **Analyzing the Options**:
- **Angular Momentum**: This is defined as the product of the moment of inertia and angular velocity. It is not directly related to the moment of a couple.
- **Force**: This is a vector quantity that causes an object to accelerate. It does not represent the moment of a couple.
- **Impulse**: This is the change in momentum resulting from a force applied over a time interval. It is not related to the moment of a couple.
- **Torque**: Torque is defined as the rotational equivalent of linear force. It is calculated as the force multiplied by the distance from the pivot point, and it is directly related to the moment of a couple.

4. **Conclusion**:
- Since torque is the measure of the moment of a couple, we can conclude that the correct answer is **torque**.

### Final Answer:
The moment of a couple is called **torque**.