Chapter 1 - Introduction to Physics - Problems and Conceptual Exercises - Page 16: 43

$210~ft/day=7.41\times10^{-4}~m/s$

See conversion factors (inside front cover). $1~m=3.281~ft$, $1~day=24~h$ and $1~h=3600~s$ $210~ft/day=(210~ft/day)(\frac{1~m}{3.281~ft})(\frac{1~day}{24~h})(\frac{1~h}{3600~s})=7.41\times10^{-4}~m/s$