Which fo the following statement is true about friction:

Explanation

To determine which statement about friction is true, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding Friction**:
- Friction is a force that opposes the relative motion between two surfaces in contact. It acts in the direction opposite to the movement or potential movement of the object.

2. **Analyzing the Options**:
- **Option A**: "Kinetic friction opposes the motion."
- Kinetic friction acts on an object that is already in motion. While it does oppose the motion of the object, the wording of this statement can be misleading. Kinetic friction does not "oppose the motion" in the sense that it stops the object; rather, it resists the relative motion between the surfaces. Therefore, this statement is **incorrect**.

- **Option B**: "Friction opposes the relative motion between contact surfaces."
- This statement accurately describes the nature of friction. Friction indeed acts to oppose the relative motion of the surfaces in contact. Thus, this statement is **true**.

- **Option C**: "Coefficient of friction is always less than 1."
- The coefficient of friction (both static and kinetic) can vary depending on the materials in contact. While it is often less than 1, it is not a strict rule that it must always be less than 1. For some materials, the coefficient can be greater than 1. Therefore, this statement is **incorrect**.

3. **Conclusion**:
- After analyzing the options, we find that **Option B** is the only true statement about friction.

### Final Answer:
The correct statement about friction is: **B. Friction opposes the relative motion between contact surfaces.**