Vehicles carrying inflammable material usually have metallic ropes touching the ground during motion, why?

Explanation

### Step-by-Step Solution:

1. **Understanding the Problem**: Vehicles carrying inflammable materials can accumulate electric charges while in motion. This accumulation can pose a risk of sparking and potentially igniting the inflammable materials.

2. **Charge Accumulation**: As the vehicle moves, it interacts with the air and the surface of the road. This interaction can cause static electricity to build up on the vehicle. Additionally, friction between the tires and the road can also lead to charge accumulation.

3. **Types of Charges**: There are generally two types of charges that can accumulate:
- Charges due to the motion of the vehicle (kinetic charge accumulation).
...