I'm trying to help my high school kid solve some momentum problems, and one of us must be missing something simple. The question is "What has more momentum a Mack truck (ie, very large object) that is still or a small truck that is moving?" I thought that momentum=mass*velocity. If this is the case, then the Mack truck would have a 0 and the small truck would have a positive number. However, my kid tells me the answer is the Mack truck. Am I missing something? Thanks in advance.