Balloons in Accelerating System

We know that feeling when we sit in an accelerating car and we get pressed backwards into the seat. However a **helium balloon darts forward**. Helium balloons are filled with a substance that is **less dense than air**.



In accelerating or decelerating systems it's not just the objects inside the system that continue to stay or go forward after it accelerates or brakes, it's the **air as well**. All that dense air is rushing forward and muscling the helium balloon back, making it seem to move the exact opposite way of everything else in the system. **Isaac Newton** explained that a **body at rest or in motion tends to stay that way until acted upon by an outside force**. When the system accelerates suddenly, the air inside the system stays at the same place a little longer than the system itself, due to the tendency of an object to maintain its motion stuff until a force acts on it (inertia). The air is stopped by the back of the car's interior and tends to pile up there.



**Inertia** depends on the **mass** of an object. The air which is surrounding balloons has higher inertia than balloon with helium but less than balloon with carbon dioxide.