To some lucky individuals, being good at physics comes naturally. For others, getting good grades in physics takes a lot of work. Fortunately, by acquiring fundamental skills and with a lot of practice, virtually anyone can be successful. Even more than to get good grades, understanding physics can open up knowledge of the mysterious forces that govern the functioning of the world.
Steps
Part 1 of 3: Understanding the Basics
Step 1. Memorize the fundamental constants
In the world of physics, some forces, such as the acceleration of gravity on earth, are assigned mathematical constants. This is just a nice way of saying that these forces are represented by the same number regardless of how or where they are used. It is a good idea to memorize the most common constants (and their units) - often, they will not be provided in tests. Below are some of the most used constants in physics:
- Gravity (on earth): 9.81 meters / second2
- Speed of light: 3 × 108 meters / second
- Molar Constant of Gases: 8.32 Joules / (mole × Kelvin)
- Avogadro's number: 6.02 × 1023 per mole
- Planck's constant: 6.63 × 10-34 Joules × second
Step 2. Memorize the basic equations
In physics, the relationships between the many different forces present in the universe are described through equations. Some of these equations are very simple, while others are downright complex. Remembering the simplest equations and knowing how to use them is crucial in both easy and difficult problems. Even problems that are difficult and difficult to understand are often solved by using many simple equations or by modifying these equations slightly to suit the situation. These basic equations are the simplest part of physics to learn, and if you know them well, you will be able to tackle at least part of every complex problem you may encounter. Some of the most important equations are:
- Speed = space interval / time interval
- Acceleration = Change in speed / time interval
- Current speed = initial speed + (acceleration × time)
- Force = mass × acceleration
- Kinetic Energy = (1/2) mass × velocity2
- Work = displacement × force
- Power = work variation / time variation
- Moment = mass × velocity
Step 3. Study where the basic equations come from
Keeping the basic equations in mind is one thing; understanding why they work is quite another. If you can, take some time to understand how these equations were derived. This gives you a better understanding of the relationships in those equations, and makes you more autonomous in solving problems. From the moment you understand why these equations work, you will be able to use them more effectively than a simple rule, memorized parrot style.
For example, consider a simple equation: acceleration = change in velocity / time interval, or a = delta (v) / delta (t). Acceleration is the force that causes the speed variation. If an object has initial velocity v0 at time t0 and a final speed of v at time t, we can say that the object accelerates because it passes by the speed v0 to v. Acceleration cannot be instantaneous - no matter how fast it occurs, there will be a certain time difference between the moment the object travels at the initial speed and the moment it travels at the final speed. Hence, a = (v - v0/ t - t0) = delta (v) / delta (t).
Step 4. Learn the math requirements for doing physics calculations
Mathematics is often referred to as "the language of physics". Becoming an expert in the fundamentals of mathematics is a good way to improve your physical problem solving skills. Some complex physical equations require very advanced mathematical knowledge (such as derivatives and integrals) to be solved. Listed below are some math topics that can help you solve physical problems, in order of complexity:
- Pre-algebra and algebra (for basic equations for calculating the unknown)
- Trigonometry (for force diagrams, rotation problems, and angle systems)
- Geometry (for problems that have to do with area, volume, etc.)
- Analysis (to calculate derivatives and integrals of physical equations - usually for advanced problems).
Part 2 of 3: Use Strategies to Improve Results
Step 1. Focus on the important information of each problem
Physics problems often contain decoy, that is, information that is not essential to solving the problem. When you read a physics problem, identify the information that is given to you, then you must understand what result you need to arrive at. Write the equation or equations you need to solve the problem, then assign each piece of information to the appropriate variable. Ignore information that is not essential, as this can slow down the resolution of the problem.
- For example, suppose you want to calculate the acceleration of a car whose speed varies in an interval of two seconds. If the car weighs 1000 kg, starts moving at 9 m / s and ends at 22 m / s, we can say that v0 = 9 m / s, v = 22 m / s, m = 1000 t = 2 s. As mentioned above, the standard acceleration equation is a = (v - v0/ t - t0). Note that it doesn't take mass into account, so we can ignore the 1000kg weight.
- Then, we will proceed as follows: a = (v - v0/ t - t0) = ((22 - 9)/(2 - 0)) = (13/2) = 7.5 m / s2
Step 2. Use the correct drive for each problem
Forgetting to indicate the correct unit of measurement can make you lose points that are easy to get. To make sure you get full marks in solving the problem, be sure to specify the correct unit of measurement based on the information you need to express. Some of the most used units of measure in physics are listed below - note that, as a general rule, physics problems always use a metric / SI system:
- Mass: grams or cKilograms
- Strength: newton
- Speed: meters / second (in some cases kilometer / hour)
- Acceleration: meters / second2
- Energy / Work: loule or kilojoule
- Power: watts
Step 3. Don't forget small details (such as clutch, drag, etc.)
). Physical problems are usually models of real-world situations - simplifying the way things work by making situations easier to understand. In some cases, this means that there are forces that can change the outcome of the problem (such as, for example, friction) that are deliberately not considered within the problem. However, this is not always the case. If these small details are not explicitly excluded and you have enough information to take them into account in the result, be sure to take them into account for greater accuracy.
For example, suppose a problem asks you to calculate the acceleration that a 5 kg block of wood if pushed onto a smooth surface with a force of 50 Newtons. Given that F = m × a, the answer might seem as simple as solving for a in the equation 50 = 5 × a. However, in the real world, the force of the friction will be exerted in the opposite direction to the motion of the object, effectively reducing the force with which it is pushed. Leaving this detail out of the problem will cause the acceleration of the block to be slightly higher than what happens in reality
Step 4. Check your answers
A medium difficulty physics problem can involve dozens of mathematical calculations. Any mistake in any of these can lead you to a wrong result and therefore not receiving any score, so pay close attention to the math as you work and, if you have time, check everything again at the end to make sure that the scores are correct.
Instead of simply repeating the calculations you had already done, you might also try to relate them to what happens in real life to test their meaning. For example, if you are looking for the momentum (mass × velocity) of an object moving forward, you will not expect a negative number, as mass cannot be negative and velocity is negative only if it moves in the opposite direction (that is, as opposed to the direction of advancement within your frame of reference). So if you get a negative result, you've probably made some miscalculation
Part 3 of 3: Doing Your Best in Physics Lesson
Step 1. Read the topics before the lesson
Ideally, you shouldn't be discovering completely new topics in the classroom. Instead, try to read the topics that will be covered in class in the textbook the day before. Don't get fixated on the math part - right now, focus on trying to understand the general concepts. This will provide you with a good basic knowledge on which you can apply the mathematical concepts that will be explained in class.
Step 2. Pay attention during the lessons
During the lessons, the teacher will explain the concepts you saw in your readings prior to the lesson and will clarify the points that may be obscure to you. Take notes and ask questions. Your teacher will probably analyze all the math involved. When this happens try to get a general idea of "what is happening" even if you do not remember the exact derivations of each equation.
If you have any questions that torment you after class, talk to the teacher. Try to ask specific questions - this makes the teacher understand that you have been paying attention. If the teacher is not busy, he will probably be available to arrange a meeting to discuss it
Step 3. Review your notes at home
To finish the physics study and understanding task, take time to review your notes once you get home. By doing so, you will keep in mind what you have learned during the lesson. The longer you wait between taking notes and reviewing them, the more likely it is that concepts will seem "foreign" to you, so be proactive in reviewing your notes.
Step 4. Solve some practical problems
Just like in math, writing, or programming, solving physics problems is a mental skill. The more you practice this skill, the simpler you will find things. If you have a hard time with physics, make sure you get a lot of practice in troubleshooting. This will not only prepare you for the exams, but will also help you better understand and internalize the concepts.
If you are not satisfied with your results in physics, do not settle for doing the assigned tasks. Make an effort to try to solve further problems - they can be problems with your textbook, problems you find online, or even problems with practical physics textbooks
Step 5. Use the available resources
You don't have to try to understand very difficult concepts on your own; depending on your school situation, there may be different ways to get help. Look for and use any tools that can help you understand. While some resources may be paid for, most students have some free tools available. Here are some ideas:
- Your teacher (through extracurricular receptions);
- Your friends (via study groups);
- Tutor (either private or covered by the school project);
- Other types of resources (physics problem books, educational sites, and so on).
Advice
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Focus on the concepts.
You always need to have a general idea of the concepts.
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Develop your math skills.
High-level physics is essentially applied mathematics, especially analysis. Make sure you know the integrals and be able to solve them by substitution and by parts.
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When solving problems pay attention to the details.
Don't forget to include friction or inertia in the calculations.
