I'm having a bit of a disagreement with someone and I hope some of you can enlighten us. It sounds rather silly but the debate is around the physics used in a video game (Batman Arkham City). In this game, the character can jump off buildings and shape his body into a downwards dive (much like a skydiver trying to gather speed). He can then open his cape and this not only slows his descent but he can also supposedly use the resistance of his cape to then fly back upwards. My understanding of physics tells me this is in principle impossible, unless there is something like a huge upward gust of wind which provides more upward force than that provided by his (downward) weight and since the character can do this anywhere at will, it's safe to assume no such gust is present. I hope a few of you can weigh in (giggle) on the issue.