What would save you time would be to know the basic fundamentals for figuring the key on your own when no one's around to help or give you the answers. In the Yahoo Search window type in WIKIPEDIA PHYSICS ASTEROID MAGNITUDE OF FORCE and click Search. Next screen you'll see FORCE - Wikipedia, the free encyclopedia, click it. At the top of the following screen will say, FORCE (on top of the Wikipedia site) with a lot of details. Go to the top right corner (next to Read Edit View history) and type in ASTEROID. You will find everything you need to know on the next screen: methods, classifications, references, links, charts of asteroid measurements (m, km) and so on. Just scroll down through the different areas of discussion and find the info you seek. DO THE MATH ! You'll be glad you bothered. I'm glad you asked and I'm glad I bothered and took the time to find some info for you, bcuz I didn't mind. And I learned something I didn't know a lot about and now I do. So, thank you. Good luck !