Frictional force always opposes motion of a body.

Answer

To determine whether the statement "Frictional force always opposes the motion of a body" is correct or incorrect, let's analyze the concept of friction in detail.

### Step-by-Step Solution:

1. **Understanding Friction**: Friction is a force that arises when two surfaces interact. It acts parallel to the surfaces in contact and opposes the relative motion between them.

2. **Direction of Friction**: The direction of the frictional force is determined by the relative motion between the two bodies in contact. It opposes the direction of relative velocity, not necessarily the motion of the body itself.

3. **Relative Motion**: To illustrate this, consider two blocks, A and B. If block A is moving to the right with a velocity of 10 m/s and block B is moving to the left with a velocity of 2 m/s, we need to analyze the situation from the perspective of each block.

4. **Calculating Relative Velocity**:
- From block A's perspective, the velocity of block B is calculated as:
\[ V_{B \text{ relative to } A} = V_B - V_A = 2 \, \text{m/s} - 10 \, \text{m/s} = -8 \, \text{m/s} \]
- The negative sign indicates that block B is moving to the left relative to block A.

5. **Direction of Friction on Block B**: Since the frictional force opposes the relative motion, the friction force on block B (due to block A) will act to the left (opposite to the direction of the relative velocity).

6. **Revisiting the Statement**: The original statement claims that friction always opposes the motion of a body. However, we see that friction opposes the relative motion between two bodies, not just the motion of one body. Therefore, the statement is **false**.

7. **Conclusion**: The correct interpretation is that friction opposes relative motion, which can sometimes mean that it does not oppose the motion of a body in isolation.

### Final Answer:
The statement "Frictional force always opposes the motion of a body" is **false**.