1. The problem statement, all variables and given/known data A jet plane flies due south over the north pole with a constant speed of 500 mph. Determine the angle between a plumb line hanging freely in the plane and the radius vector from the center of the earth to the plane above the north pole. Hint, assume that the earth's angular velocity is 2pi radians in 24 hr, which is a good approximation. Why? 2. Relevant equations 3. The attempt at a solution Well, I just can't figure out what radius vector is this... I mean, which plane is this? And I didn't understand why the hypothesis of an earth's angular velocity of 2pi radians in 24hr is an approximation. I thought that this could be considered an exact parameter.