Question

On October 21, 2001, Ian Ashpole of the United Kingdom achieved a record altitude of 3.35 km (11 000 ft) powered by 600 toy balloons filled with helium. Each filled balloon had a radius of about 0.58 m and an estimated mass of 0.31 kg. (a) Estimate the total buoyant force on the 600 balloons. (b) Estimate the net upward force on all 600 balloons. (c) Ashpole parachuted to Earth after the balloons began to burst at the high altitude and the buoyant force decreased. Why did the balloons burst?

Answer 1

(1) total number of balloons n = 600;

radius of each balloon r = 0.58 m

mass of each balloon m = 0.31

(A) Total buoyant force Fb;

(B) Net upward force F;

where W is the net weight of balloons.

(C) The atmospheric pressure on the balloon will decrease at this high altitude, thus the balloon will expand and burst.