Two Gravity related questions that I would like checked.

Greetings once more MHF!

I have a couple of questions related to gravity that I think I have worked out fully but need to make sure of.

On all questions

Q1):

What force does earths gravity exert on a 81-kg astronaut who is orbiting in a space station at a distance from the __surface__ of the earth equal to 2 earth radii? Show your calculations. Your answer must be in Newtons.

A1):

2 radii from the earth surface is equal to 3 radii from the center of the earth.

By the inverse square law the gravitational, the gravitational force at '3d' is .

Therefore, if the astronaut weighs 81kg, he weighs at 'd'. So at '3d' he weighs

Q2):

The astronaut from the last question was launched into space by a Saturn rocket.

The upward acceleration of a Saturn rocket shortly after blast-off is . When the Saturn rocket is accelerating, what is the apparent weight of the astronaut, that is, what does the astronaut experience as the weight of his body?Show your calculations. Your answer must be in Newtons.

A2):

If then . Thus, the total force acting on the astronaut is and

Therefore, his apparent weight is 90*81=7290N.

Thank you!