An astronaut of mass 72kg orbits the Earth in a circular satellite path at an altitude of 200km.
Assume g=9.8m s−2 and R=6.4×106m.
a. (i) Derive an expression for the orbital speed v required for a circular orbit at altitude h in terms of g, R, and h.
b. (ii) Using the value of v obtained in part (i), establish an expression for the actual gravitational force acting on the astronaut at that altitude.
c. (iii) Compute the numerical value of this force for h=200km.
d. (iv) Compare the result of part (iii) with the astronaut’s weight on the Earth’s surface and comment on the apparent weightlessness experienced inside the satellite.