1 Answer | Add Yours
It is said that Archimedes discovered this principle while taking a bath and feeling easier that he normally ways: a body submerged into a fluid (a liquid or a gas) is pushed upside by a force equal to the weight of the mass of the fluid it displaces. He later called this force buoyant force.
Thus, a balloon that is inflated and is having a volume V displaces a mass of air having a weight (buoyant force)
`F_b =G_(air) =rho_(air)*V`
Because the balloon is inflated with a gas having a lower density than air (let say Hydrogen) the true weight of the balloon is
`G_("balloon") = rho_(H)*V`
Since `F_b >G¨_("balloon")` , `F_b` pushes up and `G_("balloon")` pushes down ` `there will be a resultant force that pushes up the balloon.
`F = F_b -G_("balloon")` is directed upwards.
The balloon is rising because the resultant force between the buoyant force and the true weight of the balloon is upwards.
We’ve answered 318,989 questions. We can answer yours, too.Ask a question