A communication satellite is transferred from a circular orbit of radius r to a new circular orbit of radius 2r around the same planet. Neglecting the satellite’s mass compared with that of the planet, which of the following describes how the magnitude of the satellite’s orbital speed changes after the transfer?
(a) It becomes 21 times its original value.
(b) It becomes 2 times larger than before.
(c) It becomes 21 times its original value.
(d) It remains unchanged.