A balloon is filled with a gas which is lighter than air.it is observed to rise in a air upto a certain height. State a reason why the balloon stops rising.
it stop rising when the buoyant force equals weight. Buoyant force depends on the density of air, which varies with pressure (altitude) and temperature.
The balloon stops rising because of a phenomenon called buoyancy. Buoyancy is the upward force exerted on an object immersed in a fluid, such as air or water, due to the difference in density between the object and the fluid. In this case, the gas inside the balloon is lighter than the surrounding air, so it experiences an upward buoyant force, causing the balloon to rise.
However, there are a few reasons why the balloon stops rising at a certain height:
1. Atmospheric Density: As the balloon ascends, it enters regions of the atmosphere where the air density decreases. The buoyant force that the balloon experiences is directly proportional to the density of the surrounding air. As the air becomes less dense at higher altitudes, the buoyant force decreases, eventually reaching a point where it equals the weight of the balloon and its payload. At this point, the balloon stops rising and reaches equilibrium.
2. Limited Gas Supply: Another reason the balloon stops rising is that it has a limited supply of lighter-than-air gas. Over time, the gas inside the balloon can escape or dissipate, causing the balloon to lose buoyancy. When the buoyant force decreases to the point where it is less than the weight of the balloon and its payload, the balloon stops ascending.
3. Structural Limitations: The design and construction of the balloon itself can also determine the maximum height it can reach. Factors such as the strength of the balloon material, the size and shape of the balloon, and the weight of the payload can all affect how high the balloon can go. Once the forces acting on the balloon exceed its structural limitations, it will stop rising.
In summary, the balloon stops rising because of a decrease in air density, a limited supply of lighter-than-air gas, or structural limitations of the balloon itself.