Reviewed by:
Former Admissions Committee Member, Hofstra-Northwell School of Medicine
Reviewed: 3/26/24
Preparing for the physics section on the MCAT and don’t know which equations to prioritize? Keep reading for a quick summary of important MCAT physics equations.
Are you gearing up for the MCAT and feeling a bit anxious about the physics section? You're not alone. Many aspiring doctors find themselves wondering why physics is so heavily emphasized on this pivotal exam.
The truth is that a solid understanding of physics is one of the first steps of getting into medical school. From X-rays and MRIs to blood pressure and neural circuits, the principles of physics lay the foundation of modern medicine.
But fear not! We've got you covered with a comprehensive guide to the key physics equations you need to know for the MCAT. By focusing your study time on these important concepts, you'll be well on your way to acing the physics section and taking one step closer to your dream of becoming a physician.
There are several physics topics that you could be tested on the MCAT, including work, kinematics, and sound. Below we summarize the key physics equations for each topic that you could be tested on during the MCAT.
Work, force, and energy are the bread and butter of physics. Work is a form of energy that applies force to an object to displace it.
F = m x a
The net force (F) on an object can be calculated from the product of the object’s mass (m) and acceleration (A).
W = F x d x cosθ
The work (W) done on an object by a constant force is a product of the magnitude of the force (F) and the direction in which the object is displaced (d) due to this force. Cosine theta (cosθ) is the angle between the object and the force acting on it.
Wnet = ΔKE
The total work (Wnet) done by combined forces is proportional to the change of kinetic energy (ΔKE) of an object.
KE = 1/2 x m x v2
Kinetic energy is proportional to the mass (m) of an object and the square of its velocity (v).
PE = m x g x h
The gravitational potential energy (PE) of an object is proportional to the object’s mass (m) and height (h) and to the acceleration of gravity (g = 9.8 m/s2).
P = ΔW/Δt
Power is equal to the amount of work done (W) divided by the time (t).
Work-Energy Theorem: W = ΔKE
Kinematics is a field of physics that is all about the motion of objects and systems. Unlike the work and energy section above, kinematic equations do not take into account the forces that cause motion.
V = V0 + at
This equation denotes the velocity of an object under constant velocity at time (t), which equals the initial velocity (V0) plus the product of acceleration (a) and the time interval.
V2= V02 + 2aΔx
This equation uses the initial velocity, acceleration, and displacement (Δx) to solve for the final velocity.
Δx= V0 + ½ at2
This equation uses the acceleration, initial velocity, and time interval to solve for displacement for an object under constant acceleration.
Displacement with constant acceleration: Δx = v0t + ½at²
Fluid mechanics is concerned with the mechanisms and forces related to liquids, gases, and plasmas.
P = F/A
Pascal’s law states that pressure exerted on fluid at rest is transmitted equally in all directions of the container holding said fluid. Pressure is equal to the applied force (F) divided by the area of contact (A).
P + ½ pV2 + pgh = constant
Bernoulli’s equation describes how the velocity of the fluid through a tube relates to the pressure of the fluid. P is hydrostatic pressure, p is the fluid density, V is velocity, g is the gravitational acceleration (9.8 m/s2), and h is the height of the fluid.
p = m/V
The density (p) of a substance is proportional to its mass (m) per unit volume (V).
SG = psubsance/pwater
Specific gravity is the ratio of the density of a substance (psubsance) compared to a reference substance (pwater).
Fb = pfluid x V x g
Buoyant force (Fb) is the upward force a fluid exerts on an object. V is the object’s volume, p is the object’s density, and g is the gravitational acceleration.
P = P0 + ρgz
Hydrostatic pressure (P) is the pressure (P0) exerted by a fluid at rest due to the force of gravity (g).
Archimedes' Principle (Buoyant Force): FB = ρfluidVg
This section focuses on how charged particles interact with each other in systems such as circuits.
F = - k * q1q2/r2
According to Coulomb’s law, like charges repel and opposite charges attract. The force of attraction is proportional to the production of the charges (q1q2); it is inversely proportional to the square of the distance between the charges (r2)
V = IR
Ohm’s law states that voltage (V) across a conductor is proportional to current (I) and inversely proportional to resistance (R). You can rearrange this equation to solve for current or resistance.
I = Q/t
This formula defines how charge flows through an electric circuit as a current (I). It is the quantity of charge flowing (Q) in a time period (t).
R = pl/A
This equation gives the resistivity of a wire. It corresponds to the resistivity of the material (p), the length of the wire (l), and the cross-sectional area of the wire (A).
RT = R1 + R2 + …. + RN
This equation denotes total resistance (RT) in a series combination, in which the resistors are connected end-to-end in a circuit.
1/RT = 1/R1 + 1/R2 + …. + 1/RN
This formula denotes total resistance (1/RT) in a series combination, in which the resistors’ terminals are connected to the same two nodes.
Electric Potential Energy: U = kq1q2/r
Thermodynamics is a field of physics that describes how heat relates to work and energy.
q = m * Lx
This equation describes the heat (q) required to cause a phase change of a sample of mass m. Lx can be either the latent heat of fusion or the latent heat of vaporization and is the amount of heat necessary to cause a change between a solid and liquid and a liquid and vapor, respectively.
First Law of Thermodynamics: ΔU = Q - W
Light is electromagnetic radiation detected by an organism’s eye.
n1 x sin θ1 = n2 x sin θ2
This equation describes the relationship between refraction (n) and angles of incidence (sin θ) when light passes a boundary separating two media.
1/d0 + 1/di = 1/f
This equation is used to calculate image distance and describes the relationship between object distance (do), image distance (di), and focal length (f).
Thin Lens Equation: 1/f = 1/do + 1/di
Sound is a vibration that propagates through air, liquid, and other mediums as a longitudinal wave.
V = f x λ
This equation uses the frequency (f) and wavelength (λ) of a wave to calculate the wave’s velocity (V).
Doppler Effect: fo = fs[v/(v±vs)]
Mastering physics equations will lead to your success on the MCAT. Here are some tips to help you improve your understanding and application of physics equations:
By following these tips and dedicating time to studying physics equations, you can improve your performance on the MCAT and feel more confident on test day.
A strong foundation in physics is necessary to answer passage-based questions and apply concepts to real-world scenarios. Physics comprises 25% of the Chemical and Physical Foundations of Biological Systems section of the MCAT. Working with Inspira Advantage ensures you stand out with a competitive score.
Below are some frequently asked questions about physics on the MCAT.
While it's not necessary to memorize every single physics equation for the MCAT, it's highly recommended to commit the key equations to memory. Focusing on the most important and frequently tested equations can save you valuable time during the exam.
Yes, you will need to memorize most equations for the MCAT physics section, as a formula sheet is not provided. To be well-prepared, it's best to memorize the equations beforehand to efficiently tackle the physics problems on the MCAT.
One of the most effective ways to memorize equations for the MCAT physics section is by consistently practicing questions. Regularly applying the equations to solve problems helps reinforce your understanding and makes recalling them during the exam more natural.
Physics questions make up a significant portion of the Chemical and Physical Foundations of Biological Systems section, which is one of the four sections on the MCAT. Expect around 25% of the questions to be physics-focused, which translates to approximately 57 questions out of the 230 total questions on the MCAT.
Mastering the physics equations for the MCAT may seem like a formidable task, but with the right approach and mindset, you can conquer this challenge and boost your score on test day.
Remember, understanding the fundamentals, memorizing key equations, and practicing consistently are the keys to success. Don't be afraid to break down complex problems into manageable steps, pay close attention to units, and seek help when needed.
By dedicating yourself to studying these physics concepts and applying them to real-world scenarios, you'll not only excel on the MCAT but also lay the foundation for a successful career in medicine. With determination and the right tools at your disposal, you've got this!
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