Question

A hot air balloon has a volume of 440×10^3 m.calculate the buoyant force that the surrounding cold air exerts on the balloon? given that the density of the surrounding air is 2.58kg/m3

Answer 1

Hey kid! Did you understand archimedes principle? If not study it properly and try again before looking onto the answer!

Buoyant Force = Weight of the volume of cold air displaced by the balloon due to it's presence.  (That's what actually archimedes noticed)

So how to find --  Weight of the volume of cold air displaced by the balloon due to it's presence?

What is the volume displaced? 440000m³? Then how much mass does this volume of air correspond to? Think about it! and atlast multiply the mass with "g" to get the right answer!