A person is holding a suitcase and moving on a horizontal platform. Is he doing any work?

Explanation

To determine whether the person holding a suitcase and moving on a horizontal platform is doing any work, we can analyze the situation using the concept of work in physics.

### Step-by-Step Solution:

1. **Understanding Work Done**:
Work done (W) is defined as the product of the force (F) applied on an object and the displacement (r) of that object in the direction of the force. Mathematically, it is expressed as:
\[
W = F \cdot r = F \cdot r \cdot \cos(\theta)
...