F=Gm1m2/r² Puzzle Giveaway (my first puzzle)

Hi, boys and girls.
Welcome to my first Puzzle Giveaway!
It's not difficult, I assure you.
And I hope you have fun.

As is customary, (and also, common sense) please don't write here or anywhere else the answers. Let's play, shall we?
Every question has a hint, already. And you have more than a week to solve it.
If, even so, just few (or none) ones manage to solve it, I'll intercede, but I really doubt it will be necessary.
Good luck and have fun.

http://www.itstoohard.com/puzzle/UT0ss2vq