Question

The space shuttle is in a 250−mile-high orbit. What are the shuttle’s orbital period (in minutes) and its speed?

Answer 1

We diagram the problem, as in Fig.  We need to convert 250 mi to m:

but to find the radius of the shuttle’s orbit (that is, its distance from the center of the earth) we must add this to the radius of the earth. Thus:

Having the radius of the orbit, and knowing the mass of the earth, we can use  to get the period of the orbit:

Then:

We can get the speed of the shuttle using