earth's surface. 11. State the period of the earth about the sun. Use this value to calculate the angular speed of the earth about the sun in rad s ¹. The mass of the earth is 5.98 x 1024 kg and its average distance from the sun is 1.50 x 10¹1 m. Calculate the centripetal force acting on the earth. What provides this centripetal force? (L, AS/A PH1, June 1997)