Newton’s version of kepler’s third law is p2 = 4 π2 / [g (m1 + m2)] · a3, where g is the gravitational constant, which is equal to 6.67*10-11 m3 kg-1 s-2. nasa's new horizons mission found that pluto's moon charon orbits pluto every 6.1 days at an average distance of 2.0 km. what is the combined mass (in kg) of pluto and charon?