As the space shuttle orbits the Earth, the shuttle and the astronauts accelerate towards the Earth with the same acceleration. What effect does
this create?

a=g.  

the body is in one of these INGRAVIDITY, so the weight of the body would be ZERO

Explanation:

When the spacecraft revolves around the Earth, it is subjected to Newton's second law

          F = m a

where the force is the universal attractive force, the mass of the astronauts, and the centripetal acceleration.

         a = F / m

         a = (G M m / r²) / m

         a = G M / r²

the amount of is the acceleration of gravity at height r.

         a = g

Therefore, we see that the acceleration of the body is equal to the acceleration of gravity, which is why the body is in one of these INGRAVIDITY, so the weight of the body would be ZERO

since you're a real machine, your ama is always less than your ima, because you can never totally eliminate friction.

it about 600 mph from what i calculated