70. A 9.00-kg object starting from rest falls through a viscous medium and experiences a resistive force R = -by, where v is the velocity of the object. If the object reaches one-half its terminal speed in 5.54 s, (a) determine the terminal speed. 78.3 m/s (b) At what time is the speed of the object three-fourths the terminal speed? 11.1 s (c) How far has the object traveled in the first 5.54 s of motion? 121 m