How To Solve Physics Problems: Method & Examples
Matthew has a Master of Arts degree in Physics Education. He has taught high school chemistry and physics for 14 years.
Amanda has taught high school science for over 10 years. She has a Master’s Degree in Cellular and Molecular Physiology from Tufts Medical School and a Master’s of Teaching from Simmons College. She is also certified in secondary special education, biology, and physics in Massachusetts.
Solving Problems In Physics
- Describe the process for developing a problem-solving strategy.
- Explain how to find the numerical solution to a problem.
- Summarize the process for assessing the significance of the numerical solution to a problem.
Problem-solving skills are clearly essential to success in a quantitative course in physics. More important, the ability to apply broad physical principlesusually represented by equationsto specific situations is a very powerful form of knowledge. It is much more powerful than memorizing a list of facts. Analytical skills and problem-solving abilities can be applied to new situations whereas a list of facts cannot be made long enough to contain every possible circumstance. Such analytical skills are useful both for solving problems in this text and for applying physics in everyday life.
Although there is no simple step-by-step method that works for every problem, the following three-stage process facilitates problem solving and makes it more meaningful. The three stages are strategy, solution, and significance. This process is used in examples throughout the book. Here, we look at each stage of the process in turn.
How To Use The Guess Method
The GUESS method is an algorithm that should be used as a starting point for every physics problem:
- Identify the Given- When presented with a physics problem, there is always some information that is known right from the start that can be used to base a calculation. Some problems might give values such as describing a ball with an initial velocity of 3.0 m/s. Other physics problems are worded in such a way that the known data is not always obvious. For example, if presented with a problem which states something similar to “Todd threw a ball 3 m, find the final velocity of the ball”, 3 m is given directly, but the fact that gravity is acting on the ball must be taken into account, with a downward acceleration of 9.81 m/s^2 and the fact that, for the ball to be thrown, its initial velocity must be 0 m/s.
- Identify the Unknown- When reading a physics problem, the information that is not known is often glaringly obvious. Despite the obviousness of what information is unknown, not every piece of unknown information is relevant. In referencing the previous example, when Todd throws the ball, how long it takes the ball to hit the ground is not known, but this information is irrelevant because it is possible to choose an equation that does not require knowing time. The important unknown in this example is only the final velocity of the ball after Todd throws it.
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Do The Algebra/trig/calculus Symbolically
Always solve for the appropriate variable symbolically first BEFORE plugging in numbers!!!
out, its okay to plug in any zeros before solving, but zeros are the ONLY numbers you should plug in at this stage.)
Why? Because its much easier to find errors in your work, not to mention to understand what you did when you look back at it later to study or consult it as a reference, if you can see the algebra unobscured with numbers.
SIDENOTE: Good math grammar means writing the isolated variable on the left.
How To Solve Any Physics Problem
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Baffled as to where to begin with a physics problem? There is a very simply and logical flow process to solving any physics problem.
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Improve Your Math Skills
Physics is a subject that incorporates many mathematical elements and one way to solve physics problems more easily is by improving your skills when tackling mathematical formulas and problems.
You can study mathematics alongside physics as it will help you manage the formulas and problems better. This is easier said than done but by joining a study group or hiring a tutor, you can navigate around this problem and have someone next to you to guide you on how and what to study.
Math topics like algebra for basic equations, trigonometry for rotation problems, geometry for problems dealing with volume and area can be of great help when stuck solving physics difficulties.
Example Physics Problems And Solutions
Learning how to solve physics problems is a big part of learning physics. Heres a collection of example physics problems and solutions to help you tackle problems sets and understand concepts and how to work with formulas:
Physics homework can be challenging! Get tips to help make the task a little easier.
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Weightage Of Physics Problems In Exams
We now have learned why physics problems are important. But still, many students prefer to skip the problems. They think that solving theory questions can gain them more marks and it will take less time. But if you can go for the theory, that means you have an understanding of the theory. So you only practice a bit for solving the problems easily. This is because the problems do carry a lot of weightage. Of course, the weighting is different for different standards but they can help you gain marks. If you solve a problem correctly with all steps and your results are rights, there is no chance of losing marks.
The weightage of problems goes on increasing as per standards. This is because it is said that the one who can solve physics problems has a perfect understanding of the topics. Which is also true to some extent.
What Are Physics Numericals & Problems
When we study physics in our academics, we do come across numerical problems often. These problems are so created that they test our logic and understanding of physics. Some numerical are straight application problems, this means that the numerical contains the direct values of the variables in the equation and you just need to substitute the values, respectively. These kinds of problems mostly test our knowledge of equations and algebra. While some are logical problems, such problems test our understanding. To solve this problem we have to implement the theory. Sometimes we have to even modify the equation, or rather than modifying we have to rearrange the equation to find the desired value.
Once we figure out the equation, solving the problem is halfway done. Then we just have to substitute the values in the variable and solve the equation algebraically.
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Where To Go From Here
Figure out what works for you, what doesnt work for you, what works for others, and the reasons behind all three. If something works for someone else but not you, see if it would be worth it to make it work for you and consider what you would have to do to make it work for you. For example, I tend to use more powerful math because doing so allows me to set up the problem and let the math do the work for me, and you might benefit from that approach.
Though I can give you what I know, the best techniques and guidelines are the ones you forge on your own through your mistakes, efforts, and achievements. If you want to do well in physics, take what I have given you and make it your own.
Physics Problems For Class 12
Physics problems for class 12th are a bit twisted but not always. Unless you are trying to go for any competitive exams like JEE, or NEET. Of course we will cover how to solve the JEE and NEET problems in different articles. But yes, coming to 12th standard problems, the questions are not so straight forward. You have to be good with your theory. For the 12th standard you need to draw the diagrams for electrostatics questions also.
Here is a video to help you solve the questions
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Consider Your Formulas And Solve Your Physics Problems
One of the essential tools to solve physics problems is the formulas. You need to understand the derivation of the formula and memorize the application part of formulas. More and more practice will help you keep them in your mind. Lets consider a simple formula to find out its real meaning,
F = ma
This formula tells you three things, for a given mass
- the more the force, the more the acceleration, which means the harder you push an object, the more it will be accelerated.
- more the mass, more the force, which means if you want to push two objects with masses of 10 kg and 15 kg respectively, you need to put more force on the second object as it is heavier.
- more the mass, lesser the acceleration, which means if you apply some force on both the above objects, the heavier one will accelerate slower than the less heavy one.
Hence, there is a lot of information stored in any formula. If you want to understand Physics and solve problems based on it, you need to understand the formulas first, which will help you memorize them quickly.
Once you have figured out the formulas, its time to solve the problem. While solving, you have to focus on your target, i.e. the variable marked with a question mark. Keep the target in mind and solve the equations.
Physics Problems Tips & Tricks
Most of the students always forget the units. Units are a very essential part of problems. The first and most important note you need to make is to check if all the values are having the same system of units. The conversion of units should be done carefully.
The next thing we need to take care of while solving a problem is the powers of tens, 10^2 here 2 is the power. Many times we come across problems where we can easily first solve the powers for example if the value is 7×10^2 + 4×10^-3 then when we can directly do 7+4×10^-1, that is our answer will be 1.1 units. Although this was a very easy example, this was just to explain the concept to you. So here you see we solved the power first. You can solve all the powers first in the problem and then adjust the decimal.
This is because as you simplify the powers your problem starts looking simple. You dont get jumbled in the problem.
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The Physics And Math With Explanations
We will assume the bars mass as m and its length as l.
Since the bar is uniform, its center of mass must be at its geometrical center for a linear rod, the center of mass is at a distance of l/2 from any end.
The component of the weight W=mg which is normal to the rod, is mg*sin.
It acts at l/2 from the pivot point, so the moment of this restoring torque about the pivot point is
T= *mg*sin and for small angles sin= this becomes T= mg
Moment of inertia about the pivot is
Physics Homework Help To Prop Up Your Grades In School
Homework given at schools is never a cause for joy for the students, even those who are good in studies. However, there are subjects in humanities that prove to be much easier for students when it comes to doing their homework. After all, you do not solve numerical applying formulae when asked to do the assignment at home in language or History. But the same is not the case with homework given in science subjects, especially physics. Even though it is a very interesting subject that explains the way things in the world around us work, most students dread mastering the theories and their applications in real life. These students look for physics homework help to complete their assignments in time as otherwise they lose important marks and grades in the final exam.
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How To Study Physics For Jee And Solve The Numerical Problems
Physics is one of the most interesting branches of Science and it is given a lot of importance in both JEE and NEET exams. While the subject is an engaging one, most of the students find it challenging to remember the formulas and solve the numerical problems present in this subject. Additionally, the questions asked in the JEE exams are also usually from moderate to difficult level.
However, students can easily master Physics and solve problems easily. In this article, we shall discuss how to study Physics for JEE and tackle different types of numerical problems.
Strategies For How To Solve Physics Problems With Ease
Two parameters can aid you in becoming a greater physics puzzle solver. Firstly, one needs to understand and learn the concepts of physics. Secondly, one should have a plan for implementing these concepts to different conditions where physics can be important. Students describe these conditions queries for how to solve physics problems. Numerous learners respond that they can understand the matter but are unable to solve the physics problems. If it is true of others too then, possibly they require to improve their problem-solving abilities. Possessing a plan to create those abilities can support the students.
How to solve physics problems can be determined as one studied to play a musical device, drive a vehicle. What may help the students more than other things is to ought a comprehensive strategy to conform to the specific problem one faces? Students can utilize various devices or tactics with various physics sections, and only the whole approach continues the same. Students have several possible collected problem-solving abilities and practices from earlier chemistry, physics, or mathematics fields. Like different fields of knowledge and experience, any of certain practices might be helpful, and any may check the growth in determining how to solve physics problems.
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What Equations Can You Use
What equations include the quantities you know and also the one youre looking for? If you have the mass of an object and a force and youre trying to find the acceleration, start with F=ma . If youre trying to find the electric field but you have the charge and the distance, try E=q/.
If youre having trouble figuring out which equation to use, go back to our first trick. What equations are associated with the topic? Can you manipulate the quantities you have to fit in any of them?
Bonus Trick: hack the units
This trick doesnt always work but it can jumpstart your brain. First, determine the units of the quantity youre trying to find and the quantities you have. Only use base units , not compound units . Multiply and divide the quantities until the units match the units of the answer quantity. For example, if youre trying to find Potential Energy and you have the height , mass , and gravitational acceleration , you can match the units by multiplying the three quantities .
Note: Unlike the other ones, this trick wont always work. Watch out for unitless constants. For example, Kinetic energy is ½*mass*velocity2, not just mass*velocity2 as the units suggest. Even though this trick isnt perfect, however, it can still be a great place to start.
Have You Hit The Point Of Frustration When Solving Problems
First, I want to reassure you that frustration is normal when solving problems and learning new things. It does NOT mean you are stupid. It means that your brain thought it detected a pattern or recipe for solving problems while you were doing the easier, introductory problems and is suddenly finding out that the recipe doesnt work for more complicated ones this is actually a sign that youre about to break through to a deeper understanding!
Rather than trying to memorize algorithms for solving problems, which will lead you to dead ends, think of it as putting together a jigsaw puzzle. You need to find the correct pieces and then assemble them. The method below helps you do this by having you pull the information out into a list so you can easily see what you do and dont know and can start to match it up with formulas.
Another sticking point is that you may need to combine more than one formula. How do you know when thats the case? When you look at the formulas that contain the variable you need to find and you dont have all of the information to plug into any of them, its time to pull in another formula to find the missing piece. Ill write more on that in another post as I roll out my formula sheets that have been arranged to help with thinking through that part.
If youd like a free abridged one-page printable of the steps below plus a printable worksheet to help remind you of what to do, just sign up for my mailing list and youll get the download right away.
Dont Plug Numbers In Until You Have To
Because Ive been using this technique throughout all my examples, I wont give an example of this guideline.
Keeping everything in variables has several benefits:
- You can kind of tell if an answer makes sense by changing the given values to their logical extremes. For example, if the force of gravity goes up as you move away from a mass, you probably made an error somewhere.
- Its much harder to find which specific step led to an error in a series of arithmetic operations than it is to find an error in a series of algebraic operations.
- Variables will often cancel out leaving you with a simpler equation and less work to do.
- As we did in the An Advanced Trick section, both examples in the Look at Each Dimension Individually section, and the Energy Conservation example, you can often find parts of the expression that you can convert into something you already know and reduce the amount of arithmetic you have to do.
You can generalize this principle to things like not expanding everything out until you have to, such as not breaking things into individual dimensions until you have your equations, not expanding factored polynomials, etc. You should also look for simplifications you can make in the math, whether by factoring out variables, making the variables dimensionless, introducing constants, etc.