Originally Posted by
sensor_validation
Post #710
Originally Posted by Dutch M
The energy exchange Ekin vs Epot, is in general only valid for speeds in the direction of the change of Epot (ie Height) and not when trading speed between perpendicular axis.
WRONG. Of course you have to make assumptions about constant windspeed, thrust=drag, g constant etc but correctly applied the maths/physics works, in 3-d vector co-ordinates - until you get close to speed of light!
The way I read Dutch M's reference to Ek and Ep exchange, is that the Ek - or speed vector - need to have a vertical component (direction of height), for the energy conservation exchange to take place. Which is CORRECT.
With no vertical component, there is no height gained/lost, and no potential energy change, or exchange. An object that goes horizontally, from zero speed, all the way to a certain speed, will not get potential energy regardless of how slow, or fast.