At the same time air density thins considerably as altitude increases. 75% of atmosphere is within 11 Km of the surface (wikipedia), the karman line is at 100 Km altitude and the effect of atmosphere after that line is considered negligible. Agni III does not have fins, since most of the time it does not need it. This is different from small fins on Agni-I, II and fins on Prithvi. For the effect of earth's rotation on atmosphere check out Coriolis effect on the atmosphere.shiv wrote:Well someone please correct me if I am wrong.Prem Kumar wrote: A simple way to look at this is the following - of you throw a ball up in the air vertically, it will always land on your hand. Both you and the ball are moving at the same horizontal speed at the time of launch.
An object thrown up from earth should keep moving in the same direction as earth unless something slows it down.The atmosphere too is moving among with the earth (otherwise we would have 1000 kmph plus winds at earth level). But I think the atmosphere does not "stick" that well to the earth's surface and rotates slower than earth if you go higher. So I suspect air resistance will inevitably kick in to slow down any object that is moving at the same velocity as the earth's surface. The deceleration should be higher flying eastwards and lower flying westwards.
Needless to say, all this "negligible effects" actually pile up and show up in CEP. That is why technologies like closed loop inertial guidance, ring laser gyros, flex nozzle etc have to come together in a compact form to field an effective missile Hence fielding such a missle is considered a technology feat. All fields of chemistry, physics, metallurgy, mathematics etc have to come together for such a system.