0
This is the buoyancy force. Archimedes is credited with first formulating this into a mathematical principle: the buoyancy force of an object is equal to the weight of fluid it displaces. In the case of a hot air balloon, the "fluid" is the outside cool air and the balloon is displacing a volume of cool air equal to the volume of the inflated balloon. So you can say the buoyancy force F = V ρ g, where V is the volume of the inflated ballon, ρ is the outside air density, and g is gravity.
A balloon can float because it is displacing this cool air with hot air which is less dense. The volume of hot air inside the balloon thus weighs less than the same volume of cold air outside the balloon. For a balloon to be float upwards, the buoyancy force has to be at least equal to the weight of the balloon (the balloon fabric, the gondola, the people, equipment and cargo, and the hot air inside).
For example, for a balloon of 100,000 cubic foot volume (typical), with outside air at 20 deg C near sea level, the buoyancy force is about 7500 lbs. This force has to lift the gondola, people, equipment and of course the hot air inside the balloon, all of which have weight. By far the greatest percentage of that total weight is the heated air inside since there is so much of it.
What else can I help you with?
What force makes a hot air balloon rise up into the air?
The upthrust exerted by surrounding air on the balloon.
What happens as you full down the balloon at the bottom of the model?
As you pull down the balloon at the bottom of the model, the air pressure inside the balloon increases, causing the air to be pushed out through the straw. This creates a propelling force that makes the balloon move in the opposite direction.
When a balloon goes up what type of friction slows it down?
Two thing slow the balloon down. First, air friction opposes its upward movement. Second, as the balloon gets higher, the air around it gets less dense, so there's not as much force propelling the balloon upward.
What is the buoyant force of a hot air balloon?
The buoyant force on a hot air balloon is equal to the weight of the air displaced by the balloon. When the air inside the balloon is heated, it becomes less dense than the surrounding air, causing the balloon to rise. The buoyant force allows the balloon to float in the air.
What are the two forces that affect a hot air balloon?
The two forces that affect a hot air balloon are buoyancy and gravity. Buoyancy is the force that lifts the balloon due to the difference in densities between the hot air inside the balloon and the cooler air outside. Gravity acts to pull the balloon back down toward the ground.
What force makes a hot air balloon rise up into the air?
The upthrust exerted by surrounding air on the balloon.
What happens as you full down the balloon at the bottom of the model?
As you pull down the balloon at the bottom of the model, the air pressure inside the balloon increases, causing the air to be pushed out through the straw. This creates a propelling force that makes the balloon move in the opposite direction.
What makes an helium balloon go up and what makes an helium balloon go down?
a helium balloon is forced upward by buoyancy. a object is forced upward by a force equal to the weight of the fluid it displaces. this also applies to gases. the gas helium is lighter than average atmospheric air, that is that equal volumes of atmospheric air and helium do not weigh the same. This means that the volume displaced by the balloon is heavier than the balloon itself. since the air weighs more it applies more force upwards on the balloon than the balloon applies downwards on the air, therefore it rises. However, a helium balloon will not go down unless a force such as large air resistance (heavy wind etc.) is applied to it. hope this helps.
When a balloon goes up what type of friction slows it down?
Two thing slow the balloon down. First, air friction opposes its upward movement. Second, as the balloon gets higher, the air around it gets less dense, so there's not as much force propelling the balloon upward.
How does hot and cold air have an effect on an balloon?
If there is warm air in the balloon, cooler air makes the balloon rise and if there is cold air in the balloon warmer air makes the balloon fall.
How do hot-air balloon pilots get their balloons back to earth?
What they do is blast cold air into the "hot" air and it makes the air molecules slow down... Thus it makes the air balloon decrease back to earth.
What makes the hot air balloon go up and down?
A hot air balloon goes up when the air inside the balloon is heated, causing it to become less dense than the surrounding air. This creates lift. To descend, the air inside the balloon is allowed to cool, increasing its density, which causes the balloon to lower.
What is the buoyant force of a hot air balloon?
The buoyant force on a hot air balloon is equal to the weight of the air displaced by the balloon. When the air inside the balloon is heated, it becomes less dense than the surrounding air, causing the balloon to rise. The buoyant force allows the balloon to float in the air.
What are the two forces that affect a hot air balloon?
The two forces that affect a hot air balloon are buoyancy and gravity. Buoyancy is the force that lifts the balloon due to the difference in densities between the hot air inside the balloon and the cooler air outside. Gravity acts to pull the balloon back down toward the ground.
Why would heating the gas in a hot air balloon make the balloon rise?
When the gas (air) in a hot air balloon is heated it becomes less dense. This makes the balloon more buoyant so it rises.Because heating the air inside the balloon makes it less dense than the air surrounding the outside of the balloon, so it will rise.
How does thermal expansion make a hot-air balloon rise?
It rises because when thermal engery is in the balloon it makes an expansion that makes the balloon fly
Why would heating a hot air balloon make the balloon rise?
Heating the air inside the balloon makes it less dense than the surrounding air, causing it to become buoyant and rise. As the air inside the balloon is heated, it expands and its volume increases. This expansion pushes the surrounding air down, creating a lift force that allows the balloon to ascend.
