lew (04/18/83)
Greg Hennessy raised the point that the Coriolis effect might interfere with the harmonic motion of an object dropped through ye hypothetical hole through the earth. Let me assuage any doubts on this point. The Coriolis force always acts at right angles to the velocity since it is proportional to "omega cross vee". Thus, frictionless walls would restrain the object without loss of energy. The centrifugal force is proportional to "omega cross omega cross ar" and so reduces the effective gravity by a constant proportion throughout the tunnel, regardless of orientation. The upshot is that the motion in a trans-planetary tunnel will remain harmonic even if the planet is rotating, other conditions being ideal of course. Lew Mammel, Jr. ihuxr!lew