Question1
The mean distance from the center of earth to the center of the moon is rem = 3.84 × 108 m. The mass of the earth is me = 5.98 × 1024 kg and the mass of the moon is mm = 7.34 × 1022 kg. The mean radius of the earth is re = 6.37 × 106 m. The mean radius of the moon is rm = 1.74 × 106 m.
How far from center of earth is the center of mass of the earth-moon system situated?
Question2
A satellite is originally in circular orbit at radius R about a planet of mass M. We wish to transfer it to a new circular orbit at radius 2R, using an in-between transfer orbit which is an ellipse with perigee R and apogee 2R. We make a brief rocket burn in longitudinal direction to switch from circle to ellipse at r = R, and another burn at r = 2R to exit the ellipse and start the larger circle. What are the two velocity changes required? What is eccentricity of the transfer ellipse? How long does transfer take?