How to Excel in Physics

Some people are fortunate to have a natural aptitude for physics. However, most of us need to work diligently to earn good grades in this subject. By mastering the essential foundational skills and practicing regularly, anyone can become proficient in physics. In fact, good grades are just one part of it; more importantly, the knowledge of physics allows us to better understand the mysterious forces that govern how the world operates.

Memorize the fundamental constants. In physics, certain forces, like the gravitational acceleration, are constants that apply universally. This simply means that these forces generally remain the same regardless of location or the manner in which they act. You should memorize the commonly used constants (along with their units) since they are rarely provided in exams. Here are a few of the most commonly used constants in physics:

• Gravitational acceleration: 9.81 m/s²
• Speed of light: 3 × 10⁸ m/s
• Ideal gas constant: 8.32 J/(mol × Kelvin)
• Avogadro's constant: 6.02 × 10²³/mol
• Planck's constant: 6.63 × 10^-34 J × s

Memorize the fundamental equations. In physics, equations are used to describe the relationships between various forces in the universe. Some equations are quite simple, while others are extremely complex. You should focus on memorizing the most basic equations and learning how to use them to solve both simple and complex problems. Even challenging exercises can often be solved using simple equations or by manipulating them to fit the problem at hand. Mastering the basic equations is an easy task, and when you encounter more difficult problems, at least you will understand part of it if you are familiar with these equations. Some of the most important equations are:

• Velocity = Distance/Time (dx/dt)
• Acceleration = Change in velocity/Change in time
• Current velocity = Initial velocity + (Acceleration × Time)
• Force = Mass × Acceleration
• Kinetic energy = (1/2)Mass × Velocity²
• Work = Displacement × Force
• Power = Work done/Time
• Momentum = Mass × Velocity

Understand the origins of the fundamental equations. Memorizing the basic equations is one thing — but understanding why these equations exist is something else. If possible, try to learn how each basic physics equation was derived. This will help you gain a deeper understanding of the relationships between the equations and allow you to approach problems more flexibly. Since you understand how the equations "work," you'll be able to apply them more effectively than simply memorizing them by rote.

• For example, consider the following simple equation: Acceleration = Change in velocity/Change in time = Delta(v)/Delta(t). Acceleration is the force that causes an object's velocity to change. If an object has an initial velocity of v₀ at time t₀ and a final velocity of v at time t, we can say the object has accelerated from v₀ to v. Acceleration is not an instantaneous quantity — no matter how quickly the event happens, there will be a time difference between when the object begins moving at its initial velocity and when it reaches its final velocity. Thus, a = (v - v₀)/(t - t₀) = Delta(v)/Delta(t).

Learn the necessary mathematical skills for solving physics problems. Mathematics is often called the "language of physics." Mastering the fundamentals of mathematics is a great way to improve your ability to solve physics problems. Some complex physics equations require special mathematical skills to solve (such as derivatives and integrals). Below are some mathematical topics that can help you with physics problems (listed by complexity):

• Pre-algebra and algebra (for basic equations and problems like "finding unknown quantities")
• Trigonometry (for force diagrams, rotational problems, and inclined systems)
• Geometry (for problems involving area, volume, etc.)
• Pre-calculus and calculus (for calculating derivatives and integrals of physics equations — advanced physics topics)
• Linear algebra (for vector calculations — usually advanced physics topics)

Focus on the important information in each problem. Physics problems often contain "extra" information — details that are not necessary to solve the problem. When reading the problem statement, you need to distinguish between the given information and identify what you're trying to find. Write down the equations needed for the problem and then assign the provided information to the appropriate variables. Discard any unnecessary information, as it wastes time and makes it harder to spot the correct solution.

• For example, let's say we need to find the acceleration of a car when its velocity changes after 2 seconds. If the car weighs 1,000 kg, starts with a velocity of 9 m/s, and reaches a final velocity of 22 m/s, we know v₀ = 9 m/s, v = 22 m/s, m = 1,000 kg, t = 2 s. As mentioned, the acceleration equation is a = (v - v₀)/(t - t₀). Note that this equation doesn't involve mass, so we can ignore the car's mass of 1,000 kg.
• Therefore, the equation is solved as follows: a = (v - v₀)/(t - t₀) = ((22 - 9)/(2 - 0)) = (13/2) = 6.5 m/s²

Always use the correct units for each problem. You can easily lose points if you forget to include a unit or if you use the wrong one. To earn full marks on your answer, make sure to use the correct units. Below are some commonly used units for physical quantities — as a general rule, physics problems usually employ the metric/SI system:

• Mass: Gram or kilogram
• Force: Newton
• Velocity: meters/second (sometimes kilometers/hour)
• Acceleration: meters/second²
• Energy/Work: Joule or kilojoule
• Power: Watt

Don’t forget the small details (like friction, drag, etc.). Physics problems often simulate real-world situations, but they simplify the actual operations of objects to make the scenario easier to understand. Sometimes, forces that could change the outcome (such as friction) are either simplified or deliberately omitted. However, not every problem is like this. If the problem doesn't clearly state that these minor details have been excluded, and you have the information to account for them, consider including these forces for the most accurate answer.

• For example, if the problem asks for the acceleration of a 5 kg block sliding on a flat surface when pushed with a force of 50 newtons, you might think you can simply solve the equation 50 = 5 × a. But in reality, friction will oppose the motion of the block, significantly reducing the effective pushing force. Ignoring friction would lead to an acceleration slightly higher than what the block would actually experience.

Double-check your answer. A medium to difficult physics problem can involve many calculations. A mistake at any step could lead to an incorrect answer, so you need to pay close attention to your calculations. If you have time, check your answer carefully to ensure the calculations are correct.

• While redoing the problem is one way to check, you should also use your intuition to evaluate the relationship between the problem and real-world situations. For instance, if you're calculating momentum (mass × velocity) for an object moving forward, the answer cannot be negative, because mass is positive, and velocity can only be negative if the object is moving in the "negative" direction (i.e., opposite to the forward direction in your chosen reference frame). Therefore, if the answer is negative, it's likely that you've made a calculation error somewhere along the way.

Preview the lesson before class. Ideally, you should prepare ahead of time to avoid getting confused by new physics concepts during class. You should read through the textbook lesson before attending the next class. Avoid focusing too much on the mathematical aspects of the physics topic at this point — your goal should be to grasp the general concepts and understand what the teacher is explaining. This will establish a solid knowledge base that will help you apply the mathematical skills you will learn in class later on.

Stay focused during class. In class, the teacher will go over concepts you've already previewed at home and clarify any points you might not fully understand. Take notes and ask plenty of questions. The teacher may briefly cover the mathematical aspects of the physics topic. If they do, your goal should be to grasp the main idea of what they're teaching, even if you don't recall the exact steps to calculate derivatives of equations — developing the ability to listen and understand is incredibly beneficial.

• If you have lingering questions after class, be sure to ask the teacher. Try to ask very specific questions — this shows that you were paying attention during the lesson. If the teacher isn’t busy, they may schedule extra time to explain the topic again and help you grasp it better.
• You might also ask if the teacher would allow you to record the lecture to listen to later. This way, you can revisit the material and seek clarification if anything remains unclear after reviewing the lecture.

Review your notes at home. To solidify your understanding and improve your knowledge of physics, make it a habit to review your notes at home whenever you can. This routine will help you remember what you've learned in class. The longer you delay reviewing, the harder it becomes to retain the material, and the concepts may start to feel more "distant". Be proactive and strengthen your understanding by reviewing your notes regularly.

Practice solving problems. Just like math, writing, or programming, solving physics problems is a thinking skill. The more you practice, the better you will become. If you’re struggling with physics, solving more problems is essential. Not only will this help you prepare for exams, but it also helps deepen your understanding of the concepts as you work through the problems.

• If you're not satisfied with your physics grades, don't just stick to the homework problems assigned by the teacher. Challenge yourself with harder problems that you wouldn’t typically encounter — these could be problems in the textbook that weren’t assigned, free exercises online, or problems in physics workbooks (available at bookstores).

Utilize available support resources. You don't have to face a challenging physics course alone — depending on your learning environment, there are plenty of ways to seek help. Look for and use any resources that can help you understand physics better. While some resources might come with a fee, most students can access at least a few free and easy-to-find options. Here are some suggestions for where you can seek support in learning physics:

• Your teacher (schedule a meeting after class)
• Friends (study groups or doing homework together)
• Tutors (either hired privately or provided through school programs)
• Third-party resources (such as physics workbooks, websites like Khan Academy, etc.)

• Focus on the concepts. Visualizing what the teacher explains is always a valuable approach.
• Develop your mathematical skills. Advanced physics is largely applied mathematics, particularly calculus. You need to understand how to perform integrals and solve equations using substitution or by solving them piece by piece.
• Pay attention to every detail when solving problems. Don't forget to account for friction or neglect the rotational inertia when solving for moments of inertia.
• Learn how to compute derivatives.
• Discuss your homework and the material you're studying with your classmates. This will be beneficial for both you and them.