State the S.I. unit of moment of couple.

Explanation

To find the S.I. unit of the moment of a couple, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of a Couple**:
- A couple consists of two equal and opposite forces that are parallel to each other. These forces create a rotational effect about a point or axis.

2. **Define the Moment of a Couple**:
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