So download that PDF. But this time, do not just solve for ( x ). Ask yourself: Where would this equation break in real life?

A quality PDF does not just give you the answer key. It gives you the cognitive walkthrough . It shows you why choosing "B" was a trap (because you forgot the initial direction of the vector) and why "C" is correct (because the question asks for magnitude , not direction). To prove you are in the right place, try this. No calculator needed.

A. Satellite X moves faster. The lower orbit requires higher speed to balance gravity.