"In hilly areas, sand is thrown on tracks covered with snow ". Why ?

Explanation

To understand why sand is thrown on tracks covered with snow in hilly areas, we can break down the reasoning step by step:

### Step-by-Step Solution

1. **Understanding Friction**:
- Friction is the force that opposes the relative motion of two surfaces in contact. It is crucial for movement, especially for vehicles on tracks.

2. **Snow and Friction**:
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