Why is it advised to tie any luggage kept on the roof of a bus with a rope?

Explanation

To understand why it is advisable to tie luggage kept on the roof of a bus with a rope, we can break down the explanation into a few steps:

### Step-by-Step Solution:

1. **Understanding Inertia**:
- Inertia is the tendency of an object to resist changes in its state of motion. An object at rest will stay at rest, and an object in motion will stay in motion unless acted upon by an external force.

2. **Scenario of the Bus Starting**:
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