A porter carrying load on his head moves up a staircase. Is he doing any work?

Explanation

To determine whether the porter is doing work while carrying a load up a staircase, we can analyze the situation step by step.

### Step 1: Understand the concept of work
Work is defined in physics as the product of the force applied to an object and the displacement of that object in the direction of the force. Mathematically, it is expressed as:
\[ W = F \cdot d \cdot \cos(\theta) \]
where:
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