In this paper, equations of a slender body motion in flow which were derived in Part 1 of this series have been ap-plied to the falling motion in the hydrodynamic entrance region of a horizontal rectangular duct . The calculated results in this flow have been compared with those in both uniform and fully developed flow. Influences of fluid velocity and slender body length on the behaviors of the body have been investigated . The validity of this theoretical analysis has also been discussed by comparison with the experimental results . The obtained results are as follows :
(1) The trajectory of the body mass center in the hydrodynamic entrance region forms a curve composed of both the trajectory curve in uniform flow and that in fully developed flow. In this flow, the fluid velocity influences the trajectory to a medium degree among three different flow states . It has been found that the body with small length rotates its posture into vertical in the bottom boundary layer region, but in the case of longer length the body does not rotate into vertical. This result is contrary to that in fully developed flow. However it should be noticed that this phenomenon is related to the rectangular duct height.
(2) The translational and angular yelocity against the inclination angle in this entrance region change in the range between the curves which express those changes in uniform and fully developed flow. The flow development depends on the mean fluid velocity and the influences of the fluid velocity on the body behaviors contain this effect, so that its influences are less clear than those in other two flows. It is found that the longer body has a larger angular velocity within the extremely small region immediately after the begining of the motion for the reason that the present calculations are carried out under the condition of relatively small flow development.
(3) The body behaviors and the influences of fluid velocity and body length obtained by numerical calculation almost agree with experimental results. So that, it is valid to calculate the motion of a slender body in flow by means of the equations of motion derived in this series.

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