Circular and Satellite Motion - Mission CG8 Detailed Help


A satellite is orbiting the Earth. If the mass of the Earth were somehow increased by a factor of 3 (without altering the mass or orbital radius of the satellite), then the orbital speed of the satellite would ____ by a factor of ____.


 
The orbital speed (v) of a satellite about a planet is given by the equation
 
 v = SQRT (G•Mplanet/R)

where Mplanet is the mass of the planet and R is the radius of the orbit.


 
Equations should always guide your thinking about a question like this. As expressed in the Formula Frenzy section, the orbital speed of a satellite is dependent of the mass of the planet that it orbits.  The equation suggests a directly proportional relationship between orbital speed (v) and planet mass (Mplanet). Increasing the planet mass will increase the orbtial speed. And the factor by which the speed increases equal the factor by which the planet mass was increased.