Posted by Taylor on .
A satellite is in a circular orbit around an unknown planet. The satellite has a speed of 1.55 104 m/s, and the radius of the orbit is 5.50 106 m. A second satellite also has a circular orbit around this same planet. The orbit of this second satellite has a radius of 8.70 106 m. What is the orbital speed of the second satellite?

physics 
bobpursley,
You can do this with Kepler's law, or with mechanics.
With mechanics
FIrst satellite
gravity force=centripetal force.
GMm/5.5E6^2= mv^2/5.5E6
solve for GM
Next satellite, do the same thing, but you know GM, so solve for v