50 small round balloons float in a volume with surface area 10m x 10m, and a width of 0.5 meter. Each balloon has a diameter of 0.2 meter.
a) Calculate the number density (in m^-3) of balloons?
b) Calculate the fraction of the total surface blocked by balloon?
c) If bullets are used to hit balloons, find the maximum impact parameter (in m) to hit a balloon? Find the cross section (in m^2) for hitting a balloon? Find the typical scattering angle (in degrees) of a bullet?
d) If ping-pong balls (diameter=3 centimeter) are used to hit balloons, Find the maximum impact parameter (in m) to hit a balloon? Find the cross section for hitting a balloon?