1. (a) How big can a bug be and still be able to hold onto the ceiling using van der Waals forces? Assuming: the bug has density equal that of water, the bug is cubical with length L and is in pretty close contact with the ceiling, so that D=5nm and A=1kT. b) What happens if the bug is spherical with radius R ? 2. A region of charged cloud consists of spherical water droplets of radius R=0.5m each carrying a charge of +100e. The droplets repel via Coulomb force and attract via van der Waals force with Hamaker constant of 41020J. If the total interaction energy is: W=40(2R+D)n2e212DAR, what is the energy barrier for coalescence and at what separation does it occur