1. exkape speed from erth=25,039 mph or 40,320 kilo / our
This based on erth mass & yuniversal konstant av gravity (Nuetons law)
2. speed av serkluer orbit at erths surfus=exkape speed/root(2)
=25,039/1.41421356
=17,705 MPH
3. speed av serkel orbit at hier altitudes...speed drkreez bi 1/square root
meen erth radius=12,756,475 meters or 3,963.253 miles
850 km abuv surfus...R=12756+850 km=13606 km
gravity drop as 1/r^2 (G*mass/r*r)
sentrifigal foers per yunit mass=v*v/r=gravity=(Gm/r*r)
v*v=r*(Gm/r*r)=(Gm/r)
so v=square root(Gm/r)
for r=13606, kompared at surfus r=12756..=1.066*erth radius
so orbit speed at 850 km=1/root(1.066)*orbit speed at erth surfus
At erth surfus, orbit speed=28510.5 km/our
at hite=850 km, divide bi root(1.066635)=1.03278
28510.5/1.03278=27605.6 km/our