when the bob of a simple pendulum swings, the work done by tension in the string is :

Options

A. (a)`gt 0`
B. (b)`lt 0`
C. (c)zero
D. (d)maximum

Answer

To solve the question regarding the work done by tension in the string of a simple pendulum, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Motion of the Pendulum**:
- A simple pendulum consists of a bob attached to a string that swings back and forth in a circular arc.

2. **Identify the Forces Acting on the Bob**:
- The main forces acting on the bob are the tension in the string (T) and the gravitational force (mg).

3. **Direction of Tension**:
- The tension in the string always acts along the radius of the circular path of the pendulum.

4. **Direction of Displacement**:
- The displacement of the bob as it swings is along the arc of the circle, which is tangential to the circular path.

5. **Angle Between Tension and Displacement**:
- The angle (θ) between the tension force and the displacement of the bob is 90 degrees (90°), since tension acts radially inward while displacement is tangential.

6. **Calculate Work Done**:
- The work done (W) by a force is given by the formula:
\[ W = F \cdot S \cdot \cos(\theta) \]
- In this case, substituting the values:
\[ W = T \cdot S \cdot \cos(90°) \]
- Since \(\cos(90°) = 0\), we have:
\[ W = T \cdot S \cdot 0 = 0 \]

7. **Conclusion**:
- Therefore, the work done by the tension in the string when the bob of a simple pendulum swings is **0**.

### Final Answer:
The work done by tension in the string is **0**.