Consider a collection of a large number of dust particles each with speed v. The direction of velocity is randomly distributed in the collection. What is the magnitude of the relative velocity between a pairs in the collection?

• A. \[\frac{3v}{\pi }\]
• B. \[\frac{4v}{\pi }\]
• C. \[\frac{2v}{\pi }\]
• D. \[\frac{v}{\pi }\]