The flow of blood through the aorta can be approximated with the volumetric flow rate equation. When the smooth muscle of the aorta contracts, the radius can decrease by as much as 10%. If the blood flow is to remain unchanged, what must happen to the velocity of blood flow in the aorta?
A. Decrease by approximately 10%
B. Increase by approximately 10%
C. Increase by approximately 25%
D. Remain unchanged
Click for Explanation
The volumetric flow rate equation is Q = A x v where A is the cross-sectional area of the pipe, Q is the flow rate, and v is the velocity of the fluid.
The problem states that Q is to remain unchanged. That allows us to set up the following equation:
Q = A1v1 = A2v2
Plugging in 1 as the original values, we get:
1 x 1 = 0.81 x v2
Because the radius was decreased to 90% of its original value, the cross-sectional area will be reduced to 81% of its original value (A is proportional to radius squared and 0.92 = 0.81)
r2 = 0.9r1
A2 = 0.81A1
Solving for v2 we get 1.23. Thus the velocity increased by approximately 25%, making choice (C) correct.
Want more MCAT practice?
We’ve got options for every schedule and learning style!
From the best online MCAT course created by top instructors with 524+ MCAT scores to the most representative full-length practice exams and private tutoring, we can custom tailor your MCAT prep to your goals!
Not sure which option is right for you? Schedule a free MCAT consultation with an MCAT expert using the form below. No obligation, just expert advice.
Related Post
Search the Blog
Free Consultation
Interested in our Online MCAT Course or one of our One-on-One MCAT Tutoring packages? Set up a free consultation with one of our experienced Academic Managers!
Schedule NowPopular Posts
-
MCAT Blog How To Prep For The MCAT During COVID-19 -
-
-
MCAT Blog How is the MCAT Scored? -
MCAT Blog Should You Retake the MCAT? -
-
Free MCAT Practice Account
Need great MCAT practice?Get the most representative MCAT practice possible when you sign up for our free MCAT Account, which includes a half-length diagnostic exam and one of our full-length MCAT practice exams.
Learn More
Submit a Comment