Chapter 5, Problem 67P

(II) An object moving vertically has $\stackrel{\to }{v}={\stackrel{\to }{v}}_0$at t = 0. Determine a formula for its velocity as a function of time assuming a resistive force F = −bv as well as gravity for two cases: (a) ${\stackrel{\to }{v}}_0$is downward and (b) ${\stackrel{\to }{v}}_0$is upward.