A raindrop with radius R=1.5mmfalls from a cloud that is at height h=1200 mabove the ground. The drag coefficient C for the drop is 0.60. Assume that the drop is spherical throughout its fall. The density of water Pwis1000 kg/m',and the density of air P, iso.0012 gm/cm. (a) What is the terminal speed?

Two identical stars with mass m orbit around their center of mass. each orbit is circular and has radius r, so that the two stars are always on opposite sides of the circle. (a) find the gravitational force of one star on the other. (b) find the orbital speed of each star and the period of the orbit. (c) how much energy would be required to separate the two stars to infinity?