Originally Posted by mido22 While I was reading a topic I found that when a satellite orbiting the earth at a small radius it moves in a high speed more than a large radius 
yes
an inquisitive mind will take you far.....
F = m.a
m.g = m.radial accerelation
cancel mass
g=v^2/r
so square velocity is directly proportional to radius which means if the satellite is orbiting with large radius it will have more speed than small radius ????

But g is not constant with height. As the distance from Earth increases, the value of g decreases. You need to look at the universal constant G, where g = GM/(R)^2) , thus , v^2 = GM/R (M is the mass of the earth). As R increases , v decreases. An astronaut in orbit 200 miles up travels at some 18,000 mph, orbiting earth full circle in 90 minutes; A Geostationary satellite in orbit at 25,000 miles up travels at a much slower speed, orbiting earth once in 24 hours ( or about 3,000 mph, rough numbers).