Friday, September 9, 2011

Physics Problem

Lately, I have been frequenting an online forum that every pre-medical student should know of: Student Doctor Network. The forum is great because it allows like-minded individuals to talk about the medical school application process and the Medical College Admission Test (MCAT). Recently, there was a post created on a specific physics problem that I thought was intriguing (because it is related to the MCAT). People posted a variety of answers and I thought I would give the problem a shot and attempt to get a consensus. I redrew the problem for purposes of this blog and here it is:

Which container experiences the greatest pressure at the bottom of the fluid?
  A.) Container A
  B.) Container B
  C.) Container C
  D.) All containers experience equal amounts of pressure at the bottom of the fluid

...Got it yet? Some say it is "A". Some say it is "D". I thought about this problem for a bit and came up with... it depends! If the height of the water column level in each container was the same with respect to the bottom, then the pressure would be the same in all containers. Answer D.


If the volume of the water in each figure was the same, Container A would experience the most pressure. Why? Container A would have the highest water column since the cross sectional area at the bottom of the flask is the smallest out of all the containers. Container C would have a slightly lower water column height than Container A. Container B would have the lowest water column height. Since there is more area at the bottom of the Container B, the water column would be lower than the other two containers because there is more space for water to occupy. Knowing that P = pgh, we can deduce that the container with the highest water column experiences the greatest pressure at the bottom of the fluid.
Answer A.

So if you picked answer A or answer D, you are correct. The answer just depends on what assumptions you make; hence the problem is ambiguous. That basically sums up my post I made on the Student Doctor Network forums. For reference, here is the actual link to the thread:

The more practice MCAT tests I take, the more I realize that my logic is often just plain wrong! And I even think I got a "C" in one of my Physics classes during my undergrad. So if you think you have a different answer or explanation, feel free to let me know - I won't be offended that you didn't succumb to my long winded argument.


  1. Welcome to Paradise city Axl, where the grass is green and the girls are... you know.