[12003] clarification to PS#4, Q#3

[Michael J Ring]

Hi folks,

Some of you have asked about the solution to question number 3, where
you need to look for a change in speed of a ring of air, du, as a function
of change in latitude, d(phi). In the second part of the problem you're
asked to calculate d(phi) for a 10 m/s change in u. However, some of you
have correctly noted your answer to the first part depends on u and phi,
so the answer to the second part will vary depending on where you start. 
If you haven't done the problem yet, feel free to assume the ring is
initially stationary and at 45 degrees for the second part. If you've already 
done the problem and assumed other initial conditions, that's OK too; just make
clear the initial conditions you've assumed.

Thanks,
-Mike