A body of mass 1 kg is rotated in a horizontal circle of radius 1 m and moves with velocity `2 ms^(-1)` The work done in 10 revolutions is

Options

A. 40 J
B. 20 J
C. `4xx2pi(10) J`
D. zero

Answer

To solve the problem, we need to determine the work done by the body as it completes 10 revolutions in a horizontal circle.

### Step-by-Step Solution:

1. **Understanding the Motion**:
- The body is rotating in a horizontal circle with a radius of 1 meter.
- The mass of the body is 1 kg and its velocity is 2 m/s.

2. **Defining Work Done**:
- Work done (W) is defined as the dot product of force (F) and displacement (s):
\[ W = F \cdot s \]
- In circular motion, the force acting on the body is the centripetal force, which is directed towards the center of the circle.

3. **Analyzing Displacement**:
- After completing one full revolution, the body returns to its original position.
- Thus, after completing 10 revolutions, the body also returns to its starting point.

4. **Calculating Displacement**:
- The total displacement of the body after 10 revolutions is zero because it ends up at the same point where it started.

5. **Calculating Work Done**:
- Since the displacement is zero, the work done can be calculated as:
\[ W = F \cdot s = F \cdot 0 = 0 \]

6. **Conclusion**:
- Therefore, the work done by the body in completing 10 revolutions is:
\[ W = 0 \, \text{Joules} \]

### Final Answer:
The work done in 10 revolutions is **0 Joules**.