The S.I. unit of velocity is :

Options

A. km `h^(-1)`
B. m `min^(-1)`
C. km `min^(-1)`
D. m `s^(-1)`

Explanation

To find the S.I. unit of velocity, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of Velocity**:
Velocity is defined as the rate of change of displacement with respect to time. Mathematically, it can be expressed as:
\[ \text{Velocity} = \frac{\text{Displacement}}{\text{Time}} \]

2. **Identify the S.I. Unit of Displacement**:
The S.I. unit of displacement is the meter (m).

3. **Identify the S.I. Unit of Time**:
The S.I. unit of time is the second (s).

4. **Combine the Units**:
Since velocity is displacement divided by time, we can write:
\[ \text{S.I. unit of velocity} = \frac{\text{S.I. unit of displacement}}{\text{S.I. unit of time}} = \frac{\text{meter (m)}}{\text{second (s)}} \]

5. **Final Result**:
Therefore, the S.I. unit of velocity is:
\[ \text{Velocity} = \text{meter per second (m/s)} \]

### Conclusion:
The S.I. unit of velocity is meter per second (m/s).

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