Assertion : It is possible that work done by a force on an object is different for different observes .
Reason : Work done by a force depends on frame of reference of observer .

Options

A. If both assertion and reason are corret and reason is a correct explanation of the assertion .
B. If both assertion and reason are correct but reason is ot the correct explanation of assertion .
C. If assertion is correct but reason is incorrect .
D. If both assertion and reason are incorrect .

Explanation

To solve the question regarding the assertion and reason, we will analyze both statements step by step.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that the work done by a force on an object can be different for different observers.
- To analyze this, consider a block on which a variable force \( F \) is applied, causing it to displace.

2. **Case Analysis**:
- **Case 1**: An observer is stationary with respect to the ground. For this observer, the work done \( W \) can be calculated using the formula:
\[ W = F \cdot d \]
where \( d \) is the displacement of the block. Here, the work done will be positive since the force and displacement are in the same direction.

- **Case 2**: An observer is moving with the block. For this observer, the block does not appear to move (displacement \( d = 0 \)). Therefore, the work done by the force on this observer is:
\[ W = F \cdot 0 = 0 \]
In this case, the work done is zero.

- **Case 3**: An observer is moving in the opposite direction to the block's motion. For this observer, the displacement of the block appears negative. Thus, the work done is:
\[ W = F \cdot (-d) < 0 \]
Here, the work done is negative because the force and displacement are in opposite directions.

3. **Conclusion from Assertion**:
- From the above cases, we can conclude that the work done by the same force can indeed be different for different observers, confirming that the assertion is correct.

4. **Understanding the Reason**:
- The reason states that the work done by a force depends on the frame of reference of the observer.
- Work done is defined as:
\[ W = F \cdot d \]
Here, \( F \) is the force (which is frame-independent), and \( d \) is the displacement (which is frame-dependent).
- Since the displacement changes based on the observer's frame of reference, the work done will also change.

5. **Conclusion from Reason**:
- The reason is also correct as it explains why the work done varies with different observers due to the frame of reference affecting the displacement.

6. **Final Answer**:
- Both the assertion and the reason are correct, and the reason provides a correct explanation for the assertion.