The average distance of the earth from the sun isabout 1.5×10⁸ km. Assume that the earth’sorbit around the sun is circular and that the sun is at the originof your coordinate system. (a) Estimate the speed of the earth asit moves in its orbit around the sun. Express your answer in milesper hour with the appropriate number of significant figures. (b)Estimate the angle ? between the position vector of theearth now and what it will be in 4 months. (c) Calculate thedistance between these two positions.