A large sphere of material is placed in a dissolving liquid. (a) When the radius is 1 m, it is observed to be changing at 8 cm/hour. At that instant, what is the rate at which the sphere's volume is being dissolved with respect to time? cm$/hr (b) Suppose, instead, that the liquid is known to dissolve the material at a rate of 9 m /hour, at what rate will its radius r change with respect to time when r = 1 meter? when r = 1/2 meter? r = 1 m/hr r = 1/2 m/hr (c) What happens to the rate of change of the radius in part (b) as r - 0+? r -> co? > O+ 1- 00