A man is rowing a boat upstream and inspite of that the boat is found to be not moving with respect to the bank. The work done by the man is

Options

A. zero
B. positive
C. negative
D. may be `+ve` or `-ve`

Answer

To solve the problem, we need to analyze the situation where a man is rowing a boat upstream, but the boat is not moving with respect to the bank. Let's break down the steps to find the work done by the man.

### Step-by-Step Solution:

1. **Understanding the Situation**:
- The man is rowing the boat upstream against the current of the river.
- The boat is not moving with respect to the bank, which means that the velocity of the boat relative to the bank is zero.

2. **Relative Velocity**:
- Let \( V_{river} \) be the velocity of the river (current).
- Let \( V_{boat} \) be the velocity of the boat.
- Since the boat is not moving with respect to the bank, we have:
\[ V_{boat} - V_{river} = 0 \]
- This implies:
\[ V_{boat} = V_{river} \]

3. **Displacement**:
- Since the boat is not moving with respect to the bank, the displacement of the boat with respect to the bank is zero.
- Therefore, we can conclude:
\[ \text{Displacement} = 0 \]

4. **Work Done**:
- Work done (W) is defined as the product of the force applied (F) and the displacement (d) in the direction of the force:
\[ W = F \times d \]
- Since the displacement \( d = 0 \), the work done by the man is:
\[ W = F \times 0 = 0 \]

5. **Conclusion**:
- The work done by the man while rowing the boat upstream, despite the boat not moving with respect to the bank, is **0**.

### Final Answer:
The work done by the man is **0**.