The human circulatory system isclosed—that is, the blood pumped out of the left ventricle of the heartinto the arteries is constrained to a series of continuous, branching vesselsas it passes through the capillaries and then into the veins as it returnsto the heart. The blood in each of the heart’s four chambers comesbriefly to rest before it is ejected by contraction of the heart muscle. If the contraction of the left ventricle lasts 250 ms and the speed of blood flow in the aorta (the large artery leaving the heart) is 0.80 m/s at the end of the contraction, what is the average acceleration of a red blood cell as it leaves the heart? (a) 310 m/s2; (b) 31 m/s2; (c) 3.2 m/s2; (d) 0.32 m/s2.

The human circulatory system is
closed—that is, the blood pumped out of the left ventricle of the heart
into the arteries is constrained to a series of continuous, branching vessels
as it passes through the capillaries and then into the veins as it returns
to the heart. The blood in each of the heart’s four chambers comes
briefly to rest before it is ejected by contraction of the heart muscle. If the contraction of the left ventricle lasts 250 ms and the speed of blood
flow in the aorta (the large artery leaving the heart) is 0.80 m/s at the end of the
contraction, what is the average acceleration of a red blood cell as it leaves the
heart? (a) 310 m/s2; (b) 31 m/s2; (c) 3.2 m/s2; (d) 0.32 m/s2.