Arrow Home
Arrow Site Map
Arrow Search
Arrow New User
Arrow Contact Us
Arrow Gallery
BACK to Gallery of Problems English Version French Version Submit Problem

Week-end forecast

Helium-filled meteorological balloons are regularly used to provide measurements of pressure, temperature, humidity, wind speed and other useful properties of the atmosphere at different altitudes. Consider such a balloon occupying a constant volume V (i.e. not expanding nor contracting). For rough purposes, assume that the air density ρ is a linear function of altitude h, decreasing from a maximum value at ground level to 20% of that value at h = 10 km.
a) Determine the maximum total mass mmax of the balloon and instrumentation for the balloon to start rising from the ground when released.
b) Assume that the mass m of the balloon etc. is reduced to 0.8 mmax. Determine the altitude in km at which the balloon will stop rising.


Contributed by Stavros Tavoularis, Department of Mechanical Engineering, University of Ottawa, Ottawa, Canada. Image from Jet Propulsion Laboratory.

The copyright on these problems is held by the contributors. Permission must be sought before using them in any way.