3. {19%} Suppose that the radius of an under-inated bouncyr hall with a radius of 6 inches is now increasing at a rate of 1.5 infsec during an air pumping (Fig. 1 shows the cross section of the ball). {a} Is the volume growth rate higher or lower as the radius increases? (b) How quickly the volume of the ball increases when the radius is 10 inches {which is still under the maximum limit of the ball}. {Hint: The volume of a sphere is v= {413) 1': r3, where v is the total volume of a sphere with radius r. If r is changing with time tl then v is also changing with t. Thus, v{t}= [413] n rtt)3. a volume function of t} Fig. 1