Posted by Sandra on .
In the absence of external torques, the angular momentum of a system is conserved.
An artificial satellite orbiting the Earth quadruples its kinetic energy.
Assuming no external torques act on the system, the radius of the orbit will ...
a. Decrease by a factor of 4
b. Decrease by a factor of 2
c. Remain the same
d. Increase by a factor of 2
e. Increase by a factor of 4

Physics 
Sandra,
Would the answer be b..
What I did was figured out the relationship between KE and speed. If KE quadruples, speed would only double. I am not sure about the next step though, I just used the following equation: mvr = nk; this gives me that r and v are inversely related so if v is increasing by 2, r would decrease by 2..
Is this the correct way to go about doing this, or is there another equation that can can used more appropriately for this question.. 
Physics 
bobpursley,
You have it.