Question

1. The minimum speed required to launch an object so that it remains the same distance above the ground and just falls around the Earth is called?
a. perigee speed

b. circular satellite velocity

c. Newtonian orbit velocity

d. the Keplerian speed

e. the speed of sound (or Mach 1)

Answer 1

Answer: a. perigee speed

Explanation:

Firstly, we must define what is Perigee and Apogee:

The apogee is the point in an elliptical orbit around the Earth where a body is furthest from the center of it and according to Kepler's 2nd law the speed of a satellite at this point is the lowest.

On the other hand, the perigee is the opposite orbital point. It is where a satellite is closest to Earth and its orbital speed is maximum.

Therefore, if we want to throw an object in such a way that it is orbiting the Earth at the same distance respect to the ground, the minimum speed must be that which is in the perigee.