Ground in car electrics is a wire or metal part that connects the negative terminal of the battery to the body of the car. Here’s an analogy that can help you understand this in simple terms:
Think of a car as a house. Electricity in a car is like water in a house. A battery is like a tank of water, and the mass can be compared to a water pipe that connects the tank to sinks, toilets and other plumbing fixtures.
A water pipe allows water to flow and do useful work. Likewise, mass allows electricity to flow through various car components such as the headlights, engine and radio.
Therefore, the ground is an important part of the vehicle’s electrical system, providing a path for electricity to return back to the battery. Without mass, electricity would not be able to flow in the desired direction and the car would not function properly.