Problem: I have these exercises that I need help with. They look easy and I have an idea on what to do, but the answer I get is not right. I know I'm doing something wrong and I need any help I can get. 1. The problem statement, all variables and given/known data 1.) An Earth satellite moves in a circular orbit 640 Km above Earth's surface witha period of 98.0 min. What are the a.) Speed and b.) the magnitude of centripetal aceleration of the satellite? 2. Relevant equations I want to know what is the radius that I use and if I have to change 98 min for seconds? If I have the speed I can calculate the aceleration. 3. The attempt at a solution The problem is I'm assuming that the radius is 640km and I divide that with 98.0 min but that is not the right answer.