Define work. What is SI unit of work ? What is meant by positive work, negative work and zero work ? Illustrate your answer with two examples of each type.

Explanation

### Step-by-Step Solution:

1. **Definition of Work**:
Work is defined as the energy transferred to or from an object by the application of a force that causes displacement. Mathematically, work (W) can be expressed as:
\[ W = F \cdot d \cdot \cos(\theta) \]
where:
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