This is my first question, and as a chemist, my physics vocabulary is a bit limited. A younger friend of mine asked me about a physics question from school, but I am not able to solve it, and I think the question is not providing enough information. The topic is "Kepler's Law."
The question says:
The circulation time of the ISS is 91 minutes. Which height above ground does the ISS have? What is its speed?
First, I looked up Kepler's law, but to use the third law I would need something else circulating around the earth like the moon and information on its semi-major axis.
Then, I found Newton's gravitation law which needs the masses of the two objects.
So maybe you have some other ideas that I should look up to find an answer how to calculate the semi-major axis of the ISS just from the circulation time without using google for the circulation time of the moon or the mass of the earth.