A short chain is sometimes attached to the back of a petrol tanker to?

A short chain is sometimes attached to the back of a petrol tanker to ensure the balancing of the tanker. Petrol tankers are designed to carry large volumes of liquid, and when the tank is partially filled, the liquid inside can slosh around and cause the tanker to become unbalanced. This can be dangerous, particularly when driving around corners or on uneven roads. The short chain is attached to the back of the tanker and hangs down towards the ground. As the tanker moves, the chain swings back and forth, creating a force that helps to counteract the sloshing of the liquid inside the tanker. This helps to keep the tanker balanced and prevents it from tipping over, which could cause a serious accident. It's important to note that the other options listed are not correct. A short chain does not generate more friction, caution the driver when overspeeding, or conduct excess charges to the car.