Question

an automobile will float on water as long as it doesn't allow water to leak inside. In terms of density, why does admitting water cause the automobile to sink?

Answer 1

Water entering an automobile increases its average density, causing it to become denser than water and sink due to Archimedes' principle.

Step-by-step explanation:

Admitting water into an automobile causes it to sink because it affects the average density of the vehicle. The principle at work here is Archimedes' principle, which states that a floating object displaces a volume of fluid equal to its own weight. As long as the automobile's density is less than that of water, it will float. However, when water enters the car, the car's average density increases. Once the average density of the car becomes greater than that of water, the buoyant force can no longer support it, and the car will sink.

The concept of density is key in understanding why objects float or sink—objects less dense than the fluid they are in float, and those with a higher density sink. This is based on the fact that a fluid with a higher density contains more mass and weight in the same volume. In the case of an automobile floating on water, the interior space of the car is filled with air, which is much less dense than water. When water starts leaking into the car, it replaces the air, thus raising the car's average density until it exceeds that of the water, ultimately causing the car to sink.