3. An earth satellite moves in a circular orbit of 640 km above the earth's surface with a period of 98 min. (a) Calculate the speed of the satellite. (b) Calculate the acceleration of the satellite. 4. Two satellites are in circular orbits around a planet that has radius 9.00 x 106 m. One satellite has mass 68.0 kg, orbital radius 5.00 x 10^7 m, and orbital speed 4800 m s. The second satellite has mass 84.0 kg and orbital radius 4.60 x 1047 m. What is the orbital speed of this second satellite