posted by Gharib on .
Skydiver Joseph Kittinger, record for the longest jump, reaches a terminal speed of 60m/s with his arms and body fully extended. Then, he switches to a head first dive, reducing his cross section area by 80% (that is, his cross section area when head-first is only 20% of his cross-section area when falling with arms and body extended). what is his terminal speed when falling head-first?
I know that I will be needing to use the drag force formula which is (1/4)Av^2. But have no idea how to start. Mass is not given...
thanks in advance