Blood flows in an aorta of radius 9 mm at 30 cm/s.

(a) Calculate the volume flow rate in liters per minute.

(b) Although the cross-sectional area of a capillary is much smaller than that of the aorta, there are many capillaries, so their total cross-sectional area is much larger. If all the blood from the aorta flows into the capillaries and the speed of flow through the capillaries is 1.0 mm/s, calculate the total cross-sectional area of the capillaries.