Current Attempt in Progress The aorta carries blood away from the heart at a speed of about 38 cm/s and has a radius of approximately 1.2 cm. The aorta branches eventually into a large number of tiny capillaries that distribute the blood to the various body organs. In a capillary, the blood speed is approximately 0.078 cm/s, and the radius is about 5.8 x 10'4 cm. Treat the blood as an incompressible uid, and use these data to determine the approximate number of capillaries in the human body. Number n Units v