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/s^2
(b) 31 m/s^2
(c) 3.2 m/s^2
(d) 0.32 m/s^2.
Answer: C. 3.2 m/s^2
Explanation
The average acceleration is the change in velocity divided by the time interval during which that change happened.
