Dropped objects and other motions relative to the noninertial earth

Abstract

Earth is a noninertial frame of reference due to its spin and its orbital free-fall acceleration in the gravity fields of the sun, moon, and other external attractors. Three particularly interesting aspects of motion relative to the earth are discussed: (a) the effect of the sun and the moon and other external gravitational attractors; (b) the Foucault pendulum at middle latitudes; (c) the venerable and surprising problem of the deviation of the path of a dropped object away from the plumb line. A selective review of the twentieth century physics literature on motion relative to the earth demonstrates that errors and omissions abound. A fourth example is also presented, the interesting textbook problem of the free motion of a particle on a frictionless horizontal plane, as a simple illustration of carelessly incorrect treatment in much of the literature.