Walking into MCAT preparation, many students think of physics as the least applicable science to medicine, reflecting on calculus-heavy premedical classes. But even in the medical field, physics is all around us. When we treat patients at a rehab hospital, we often talk about motion, forces, and bone strength. An ophthalmologist may draw diagrams to help students better understand myopia and hyperopia. When we talk about mitochondria functioning as the batteries of the cell, we mean that fairly literally.
MCAT Practice Questions: Physics
1. A man walks 30 m east and then 40 m north. What is the difference between his traveled distance and his displacement?
A. 0 m
B. 20 m
C. 50 m
D. 70 m
2. A 30 kg girl sits on a seesaw at a distance of 2 m from the fulcrum. Where must her father sit to balance the seesaw if he has a mass of 90 kg?
A. 67 cm from the girl
B. 67 cm from the fulcrum
C. 133 cm from the girl
D. 267 cm from the fulcrum
MCAT Physics Practice Questions: Explained
MCAT Physics Tips and Strategies
Although the designers of the MCAT will provide physiological facts and numbers, that’s not what you’re expected to know before taking the exam. Your MCAT practice will require being able to see the same concepts that you learned in your undergraduate pre-med classes in a very defined and isolated environment—applied in a foreign scope to integrated sciences.
The interplay of scientific disciplines (i.e., how your knowledge of physics or chemistry informs your understanding of how an organ works) is paramount to your success both on the new MCAT and as a future physician. The human body is a network of interdependent physical, chemical, and biological processes, and the MCAT measures your ability to make those connections.
MCAT Physics Tip 1: When studying a “physical” science, think through all of its biological applications.
For example, let’s use reduction and oxidation. We know that LEO the Lion says GER (the Loss of an Electron is Oxidation, and the Gain of an Election is Reduction). Therefore, when a metal is losing or gaining electrons, it’s either getting oxidized or reduced, respectively.
Don’t stop there. The Redbox that occurs in the Electron transport chain, with NADH losing an electron to the ETC and getting—you guessed it—oxidized, is the exact same concept. NAD+ is the product of the oxidation of NADH, just as Ag+ is the oxidized product of Ag. It’s the exact same science. So, don’t get thrown off by the fact that you learned it in two different places.
MCAT Physics Tip 2: There are a finite number of scientific facts.
There is some truth in the claim that most of biology is rooted in chemistry and physics. Take proteins for example. We think of them as biological molecules because they serve such a prominent role in the body. In reality, they are nothing more than a very specific structural arrangement of carbon, nitrogen, oxygen, hydrogen, and sometimes sulfur.
The way in which they are bonded to each other is through a bonding orbital—just like the ones you learned about in general chemistry. They fold into specific shapes because of attractions and repulsions of the amino acids in their sequence. Those are the same attractions and repulsions seen in chemistry. The proteins themselves are coded from RNA, which is coded from DNA. RNA and DNA are just chemical molecules with the same properties you learned about in chemistry.
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rephrase it*
When preparing for the MCAT, many students may initially overlook the relevance of physics to medicine. However, physics concepts are actually prevalent in various medical scenarios. For example, motion, forces, and bone strength are discussed when treating patients at a rehab hospital. Ophthalmologists may use diagrams to explain conditions such as myopia and hyperopia. Additionally, when we refer to mitochondria functioning as cell batteries, this is a literal interpretation.
Here are the explanations for the provided MCAT practice questions on physics:
1. To find the difference between the traveled distance and displacement, we need to calculate the straight-line distance from the starting point to the final position. The man walks 30 m east and then 40 m north. This creates a right triangle with sides of 30 m and 40 m. We can use the Pythagorean theorem to find the hypotenuse, which represents the straight-line distance or displacement:
Distance = sqrt((30^2) + (40^2)) = sqrt(900 + 1600) = sqrt(2500) = 50 m
Since the man's traveled distance is the sum of the distances he walked in each direction (30 m + 40 m = 70 m), the difference between his traveled distance and displacement is:
Traveled distance - Displacement = 70 m - 50 m = 20 m
Therefore, the answer is B. 20 m.
2. To balance the seesaw, the torques on both sides of the fulcrum must be equal. Torque is calculated by multiplying the force applied to an object by the perpendicular distance from the force to the fulcrum. Since torque depends on both force and distance, the father's mass and position are relevant.
The torque equation is:
Torque = Force x Distance
Since the father's torque must balance the girl's torque, we can set up the equation:
Father's Torque = Girl's Torque
(90 kg)(9.8 m/s^2)(Distance from father to fulcrum) = (30 kg)(9.8 m/s^2)(2 m)
Simplifying the equation gives:
(90 kg)(Distance from father to fulcrum) = (30 kg)(2 m)
Distance from father to fulcrum = (30 kg)(2 m) / (90 kg)
Distance from father to fulcrum = 0.67 m = 67 cm
Therefore, the answer is A. 67 cm from the girl.
In summary, physics plays a significant role in various aspects of medicine, and understanding physics concepts is crucial for success on the MCAT. Revisiting and exploring the biological applications of physics and recognizing the interplay between scientific disciplines can enhance your understanding and ability to make connections on the exam.