(a) State Kepler’s third law of planetary motion.
(a) State Kepler’s third law of planetary motion.
(b) Three hypothetical planets A, B and C orbit the same star with semi-major axes of 0.50 AU, 1.50 AU and 2.50 AU respectively. Without performing detailed numerical calculation, arrange the planets in the increasing order of their orbital periods and give a brief reason for your answer based on the law stated in part (a).
(c) Explain why, according to this law, a planet that is farther from the Sun moves more slowly in its orbit than a planet that is closer.