A six year old boy weights about 25 kg. Estimate the radius of a spherical helium balloon capable of lifting the boy.Solution 2.
B= density of air* volume *g if in air
The Attempt at a Solution
the buoyancy must be greater than the weight.
Density of helium is 4g/22.4l = 0.180 kg/m3.
Density of air (Nitrogen) is 28g/22.4l = 1.25 kg/m3.
not sure where to go from here...