Hey, first post. I've been searching around everywhere but I am yet to come up with an an equation or theorem that relateds altitude to speed and the forces that act on a plane (thrust, weight etc). I am perhaps assuming that, in at least this question, the altitude of the plane doesn't affect it's speed if the forces stay the same? Anyway here it is A business jet is traveling at a constant speed of 150 m/s while its engines provide a total thrust of 25 kN a) If it is in level flight, what is the magnitude of the total drag on the jet? (I answered with 25 kN because since it was travelling at a constant speed and in level flight, drag = thrust) b) If the jet reduces its altitude by 500m, what would be the new maximum possible speed of the jet? (This is the one I'm stuck on. The question doesn't specify the actual altitude of the plane so I've come to think that it is a bit of a trick question and the max speed is still 150 m/s because the altitude is irrelevant if the forces stay the same?) Hopefully someone can help me out with question b)...and question a) if I buggered that one up too.