I'm in search of a material that decreases in viscosity with acceleration. In this case, I really mean decelleration, but a change of velocity nonetheless. My questions: 1. Could such a material exist? Does Such a material exist? If so, what is it? 2. Would a material with said properties inside a container, subject to rapid deceleration, have more of a tendency to remain on its forward course than a solid body of equal mass in the same situation? 3. How can I mathematically describe the behavior of this material?