The radius of the earth's orbit around the sun (assumed to be circular) is 1.50 108 km, and the earth travels around this orbit in 365 days. (a) What is the magnitude of the orbital velocity of the earth in m/s? m/s (b) What is the radial acceleration of the earth toward the sun in m/s? m/s (c) Repeat parts (a) and (b) for the motion of the planet Mercury (orbit radius = 5.79 107 km, orbital period = 88.0 days). orbital velocity radial acceleration m/s m/s