It's like in Mario Kart where if you drive off the side into the mud, the drag slows you down. If you drive back to the road in a perpendicular fashion, you minimize your time in the mud, but you've built up no momentum once you get to the road. If you drive parallel and angle yourself gradually toward the road, you maximize your time in the mud and waste a lot of energy, but you get to keep whatever forward momentum you've gained once you get to the road. Depending on the thickness of the mud, there's some optimum angle that describes the most efficient path back onto the road; approaching perpendicular for thicker mud, and approaching parallel for thinner mud.Now if the thickness of the mud/atmosphere decreases as you get closer to the road/space, that optimum path would be a curve, starting at perpendicular and ending at parallel, and that's exactly what rockets do.
viernes, 6 de abril de 2012
This is how NASA explains rockets.