I’ll give you a citation from R. Feynman:

“When I was in high school, my physics teacher – whose name was Mr.Bader – called me down one day after physics class and said: “You look bored. I want to tell you something interesting.” Then he told me something which I found absolutely fascinating, and have, since that time, always found fascinating. The subject is this – the principle of least action.”

Have you heard about this principle which formulates all newtonian mechanics in one sentence? It gives a deep link with quantum mechanics. It is really mysterious and fascinating. Read about it and enjoy Newtonian mechanics. It is in fact about the deepest and fundamental properties of space and time.

It depends what you mean.

As an undergraduate you should already know most of the important stuff. By the end of your study, you will have encountered orbital mechanics, Lagrangian and Hamiltonian mechanics, wave mechanics, fluid mechanics, thermal physics and statistical mechanics and so on (some of those to a greater or lesser extent).

This means, yeah - you should be able to derive most of it - but that’s because you already know the answer’s you’re aiming for.

As my tutor says “everything is trivial when you know the answer”. For example: I can derive in about 10 minutes work it took Einstein 10 years to work out.

Am I smarter than Einstein? Clearly not - I just know what the answer I’m trying to get to is. Einstein didn’t know what the right answer was - he was an explorer, hacking his way through a jungle trying to find a lost civilization. I’m a tourist wandering down a paved road with a map.

So as an undergraduate, deriving mechanics is wholly unimpressive - and indeed, you will write down most of the derivations at some point in your undergraduate degree. The reason we hold the people who did it first in high regard is because they had the intelligence to find something completely new.

Doing something that has already been done before is not very impressive - the people who found their way to America after the original explorers discovered it aren’t genius explorers - they were merely competent sailors following what someone else had already done.

To conclude this analogy: an undergraduate degree means you are a competent sailor - you should have already proven most of the important results in mechanics, and be comfortable with using most of them off the top of your head. What makes you great is if you can do something that has never been done before.

A bit more information would've​ helped nonetheless I will make the answer general.

Doing what you love and loving what you do are two different things. I am assuming you want to make a career around maths and physics. Let's take a look at some of the options.

• Engineering is the branch which heavily relies on maths and physics especially mechanical, electronics, aerospace etc.
• Architecture if you don't mind sketching and drawing.
• Academics - Either you can do B.sc and B.ed (for school) or B.sc , M.sc and other higher degrees (for college). Only if you are interested in teaching and sharing your knowledge.
• Research if along with loving these subjects, you are equally good at it then this is the career for you. Sure you have one less zero in your salary but it will be worth it. IISC, IIT, TIFR ,BARC, DRDO , ISRO are some institutes you can look for. Although research is in itself a very vast field but there are certain areas that will interest you as you study further.

Astrophysics although it counts in research but I have mentioned it separately because

1. It is a collaboration of maths and physics.
2. It is my personal favorite.

• Writer -have some writing skills? Can use for writing in science magazines, journals for maths and physics.

These are some fields you can look for. Let me know if you need any help regarding these options like when and where.

Hope it helps.

Good luck!

I suspect you’re underestimating the complexity and sophisitication of classical mechanics.

A classic textbook is Vladimir Ilyich Arnold’s Mathematical methods of Classical mechanics (1989)

A short quote from the book might give you an idea of what this notional undergraduate would be facing. This is from his chapter: “Geodesic invariants of left-invariant metrics on Lie Groups”

So, a could a competent undergraduate physics student re-derive classical mechanics in a few years?

No.

The thing which make me love physics is not because I could understand everything intuitively, but because I love the journey to understand things intuitively. It may be hard! But as long as you are sane, you can get an intuition for most of the things provided that you spend enough time on keenly observing the nature.

You say newtonian mechanics is hard but I think you would definitely master it once you spend lots of time on it. Dont just solve loads of problems, analyze one problem deeply with an eagle’s eye.

A tip,

Understand newton’s laws deeply by plenty of examples crafted by your own. Make sure you yourself craft everything. Thats were creativity is hidden in our formalised academic system, where textbook authors design problems enhancing their intuition but not yours!

Why physics as a career??

We are living in an age of discovery. We know way less than five percent about our universe. You could be an integral part of discovering some of those.

Edit: Of course, as the other answer mention, some(yes! actually ‘many’ tbh) higher concepts dont have an intuition at all! why? because we have only limited senses : ) How much can you see in the plethora of wavelengths? how far can you see? how much can you hear? how many laws of physics can your brain simulate at once?? Far too low right? Thats why physics is hard!!

Thanks for the A2A.

Before I came to college, I too found Newtonian mechanics a very difficult aspect of physics. I found that I lacked the “intuition” that my batchmates had and that Newtonian mechanics clearly demanded from us. I was flabbergasted. But once I took physics, I realized that one need not have the “intuition”. When we learnt about the action principle, I came to know that it all has a structure which can be sorted out. Of course, to solve most of the engineering problems, one needs the “intuition” that I spoke of. But if you're doing physics, you actually need to get to the base of that “intuition”. In doing so, you can get rid of it altogether.

For instance, consider the block on an inclined slope problem where the block is given a velocity. This problem usually appears in entrance exams with the constraint that the inclined slope is typically stationary. However, if the inclined slope is free to move as well, it's a bit hard(and tedious) to solve it using the intuition that we speak of. But once you know physics, you won't even attempt that. Instead, you'll write out the Lagrangian of the system and minimize the action to get the solution. You wouldn't need to allude to forces to solve it. See how your problem with intuition gets eliminated? Well, I may stress, if the surfaces aren't frictionless, it becomes complicated even using the Lagrangian approach. And that's why there's a certain utility in trying to inculcate the intuition even in physics. I can offer you no guidance on this because I'm weak in it myself. But rest assured, it is no reason to not take up physics in the future. On the verge of getting my degree, let me be an example to highlight this.

Politics!

Okay, just kidding. Did you know Angela Merkel studied Physics?

WHAT TO STUDY:

If your interest is Physics, you should study Physics. If you can pursue what you love, and there are no roadblocks in your way (financial, controlling parent, etc.), pursuing your passion will make you happy.

Now, the whole “pursue your passion” thing is thrown around a lot. Sometimes, your passion isn't something you can pursue at university if you want to be practical and look at your education as an investment and pursuit of a marketable skill. However, your passion for Physics opens up plenty of doors (many not strictly in Physics at all), so it's safe to say, “follow it!”

See, if you don't end up doing Physics professionally, a degree in Physics will still see to it that you're solid at Math, handling highly complex and rigorous problems, and using logical thinking. You'll still have plenty of exciting career opportunities.

CAREER PATH:

Physicist (obvious):

Path: PhD a must if you want to be involved in any research or important work in the field.

Titles: physicist, researcher

This is an obvious choice if you want to make Physics your career. There aren't terribly many jobs (20,000 or so

Electrical/Electronic/Computer Engineer:

Path: MS would be needed, since you would likely need some specific E.E./C.E. experience to be competitive (and you'd need to take some courses to level up)

Titles: electrical engineer, hardware engineer

The jobs are more plentiful (just under 316,000 in E.E. alone

Professor:

Path: PhD is a must

Titles: professor, researcher, author

If you love it, surround yourself with it your whole life and teach it! Inspire the next generations, and pursue research at your university. Good to great salaries, and you do what you love. Positions are highly competitive, though, so be prepared!

Computer Scientist or Software Engineer:

Path: MS would be needed for the latter, unless you were really good at teaching yourself. For the former, an MS or PhD would be recommended, if not required.

Titles: computer scientist, researcher, software engineer, web developer

There are a crazy amount of jobs in software….over one million

There are a lot of Physics majors in software. They've got the analytical minds for it, and they love to solve problems and build things!

Shrimpin’ Boat Captain:

Path: go out and get a boat (and hope your competitors all lose their boats in a storm)

Titles: shrimp boat captain, shrimper, shrimpin’ man

I'm kidding, but only just. Life is a twisty highway with ups and downs and zigzags- it's not a straight path. You might love Physics, but find yourself somewhere else entirely…and that's okay. You can always keep your passions, even if you find others. Keep your eyes open for exciting, unexpected opportunities!

Footnotes

Interesting question.

I build humanoid robots, and do lots of kinematic synthesis .

There are a few books I would recommend:

Anything by Caron Shelby, the famous car designer, that has to do with racecar suspension design. He is very good at explaining how a mechanism affects the forces and feel of a car. The ideas can be expanded to robots.

Robot wrists actuators, by Rosheim. Good examples of interesting kinematics and actuators. A bit self serving, since the wrists designed by Rosheim are presented as the best.

The thesis of Jerry Pratt, my boss. He is quite brilliant and his thesis is well written.

Generally, I don't use many books. I mainly read journal papers, PhD thesis, and look a lot on Pinterest for ideas on robots. Artists sometimes have a much better way to convey info than researchers.

To really understand how to build a robot limb, you got to try to copy and make some yourself. Get a Lego kit, a student SOLIDWORKS licence or Onshape, if free. Try to copy some of the joints of the Atlas robot, the Spot robot, by Boston dynamics. Maybe try to understand the shoulder design of IIT iCub. The wrist of the DLR hand.

Use paper, string, sticks, Lego , 3d printed parts, whatever is available and convenient. Build some mechanisms, make them move, see how they work. I use a lot of drawing and 3d printing, to build full scale robots out of plastic. It is a bit expensive, and I wouldn't do it like this if I wouldn't be paid for it. Maybe make smaller versions.

Are you still in school? Make a robot soccer club, or join whatever robotics club is there. If you are not in school, see if there is any club or makerlab in your area.

The goal is to build a bunch of small robots, to learn how Arduino works, how 4-bar linkages work. How does a cable transmission work. How does a Series Elastic Actuator work.

Once you got a few cool projects, such as a walking quadruped with servo actuators, maybe a biped soccer robot, or a robotic arm, apply for grad school or for internships with companies making robots. The place i work with, IHMC, hires interns every summer. I am sure other places do as well. If you got cool projects to show off, send me a message.

Good luck.

It really depends on what it is you dislike about classical mechanics. If you don’t like the math, then you are just going to be more unhappy in relativity and quantum mechanics. If, on the other hand, you find that there’s not enough math for you and that you dislike how “applied” classical mechanics is, you might find you enjoy later physics classes more.

The general trend in physics is that the higher you go, the more abstract things will get. Mechanics, thermodynamics, and optics are less abstract and use simpler math. Electricity & magnetism, relativity, and quantum mechanics are more abstract and use more advanced math.

Kinematics is a fundamental topic in physics that deals with the motion of objects without considering the forces causing the motion. Understanding kinematics requires a clear grasp of key concepts and a structured approach to problem-solving. Here's a step-by-step guide to help you tackle kinematics:

1. **Define the Terms:**

- Start by understanding the basic terms used in kinematics, such as displacement, velocity, and acceleration. Having a clear definition of these terms is crucial for building a solid foundation.

2. **Understand the Equations:**

- Familiarize yourself with the kinematic equations that relate displacement, initial velocity, final velocity, acceleration, and time. The three primary equations are:

- \(v = u + at\) (velocity-time relation)

- \(s = ut + \frac{1}{2}at^2\) (displacement-time relation)

- \(v^2 = u^2 + 2as\) (velocity-displacement relation)

3. **Vector and Scalar Quantities:**

- Recognize that displacement, velocity, and acceleration are vector quantities, meaning they have both magnitude and direction. Understand how to work with vector components in kinematic problems.

4. **Graphical Representation:**

- Learn to interpret and create graphs representing motion. Graphs, such as position-time, velocity-time, and acceleration-time graphs, can provide valuable insights into the motion of an object.

5. **Practice Unit Conversions:**

- Ensure you are comfortable with unit conversions, as different systems of units may be used in kinematics problems. Consistency in units is essential for accurate calculations.

6. **Solve Problems Step-by-Step:**

- Break down kinematics problems into smaller steps. Identify the given information, determine what needs to be found, and choose the appropriate kinematic equation to solve for the unknown quantity.

7. **Pay Attention to Sign Conventions:**

- Be mindful of the sign conventions for displacement, velocity, and acceleration. Establish a consistent direction as positive and stick to it throughout the problem.

8. **Use Real-Life Examples:**

- Relate kinematics concepts to real-life examples. Understanding how these concepts apply to everyday situations can make them more intuitive.

9. **Seek Additional Resources:**

- If you're struggling with specific concepts, refer to additional resources such as textbooks, online tutorials, or educational videos. Different explanations may help reinforce your understanding.

10. **Practice Regularly:**

- Practice is key to mastering kinematics. Work on a variety of problems to strengthen your problem-solving skills and become comfortable with different scenarios.

If you find that you're still struggling with kinematics, consider seeking help from your physics teacher, classmates, or online forums. Sometimes, discussing problems with others can provide new insights and approaches. Remember to be patient with yourself, as understanding complex physics concepts takes time and consistent effort.

What you want to be? Jack of all and master of none!!!

Looking at your interests I can presume it to be engineering. Leaving chemistry aside rest three of your choices can be true if you choose to do engineering in mechatronics.

Apart from research engineering maths will not be required much.

Again I would suggest you to narrow down your interest. If you really like chemistry then go for BSc . chemical engineering would have job prospects in petrolium companies, steel industries and obviously chemical and fertilizer industry.

Mechanical is sort of know everything subject . You have maths science and everything. From mechanics to thermo to fluid to heat transfer it involves everything.

Hope I could answer to your expectations

From U of Texas - What is classical mechanics? - you can read:

"Classical mechanics is the study of the motion of bodies (including the special case in which bodies remain at rest) in accordance with the general principles first enunciated by Sir Isaac Newton in his Philosophiae Naturalis Principia Mathematica (1687)"

Therefore, yes, not only should the structural engineer learn about classical mechanics, he/she must be proficient in it. Classical Mechanics (or Newtonian Mechanics" ) are the basis upon which Structural Engineers make all their calculations.

Of course there are different ways to teach Classical Mechanics, and maybe that's the reason why your question has arisen. A Physics major student will learn C.M. in a different way from an Engineering one. The former usually go thru a calculus heavy CM course filled with all sorts of integral and DiffEq trying to prove theorems; the latter is usually exposed to a less-heavy calculus based course that's interested in applications.

Forget about the physics for a few minutes and think about the real world situations described by the theory: riding in a vehicle, tossing a ball, rolling down a hill. Unless you've been locked in a small room all your life, you already know kinematics and how motion works.

You're learning how to represent these things formally. To bridge the gap between what you already know and the formal theory, try using all of these steps:

1. Make sure you understand the terms that are being used and how they relate to your real-world experience, e.g. go faster=acceleration.
2. Start each problem by creating a table of the information you're given and need for the problem: mass, distance, velocity, acceleration, force, time. Write this over to the side where you can reference it easily.
3. Draw a diagram of the forces acting on each object, called a free body diagram. You should have learned this in class or early in your textbook. If not, watch instructional videos on YouTube and try a few examples until you can do it yourself.
4. Convert the diagram into an equation or set of equations. Easier said than done? Not really. Each arrow in the free body diagram is one term in your equation. All the terms in the equation add up to zero, according to Newton.
5. Sometimes you need to use sin and cos to convert the arrows to a uniform coordinate system. Try to understand when and why you would do this. YouTube videos can help with this too.
6. Sometimes you need to convert one or more values to a different representation to make the equations work. Use the units to determine whether this is the case: meters, kilograms, seconds. Every term in your equation(s) needs the same units or the equations won't solve correctly. Forces are always kg * m / s^2.
7. Solve the equation(s) for the variable(s) you need for your answer. If this is where you get stuck, you may need to brush up on your algebra, or just use a graphing calculator.

An invaluable tool in Physics is a cheat sheet of all the transformations, equations, and rules you are taught. This is very helpful for completing steps 4-6. If you use it enough you will be able to reference it from memory when taking a test.

The students I work with mostly struggle because they overthink the problem. They get stuck in the numbers and equations and forget they're learning about things they already know. Using the step-by-step method above makes it easy to get past this.

“Physical concepts, such as Classical mechanics, Thermodynamics and Statistical mechanics, Electromagnetism, Quantum mechanics, Atomic physics, Molecular physics, Optics, Condensed Matter Physics, Nuclear Physics etc., play a vital role in the process of innovation, which is, crucial in the development of engineering branches. Engineering is basically physics applied to create something more practical. It can be mechanical, electrical, civil, etc., but they’re all basically governed by physics. There’s no way you would solve complex engineering problems without understanding the physics behind it.”

Role of Physics in Engineering

Physics classes—especially a combination of problem solving and experiments (lab experiences)—is a process of honing or “educating” your physical intuition.

So. Work through it!

Few have a proper Newtonian intuition before they start.

Most have something more like an Aristotelian level of intuition. (Please pardon the expression, but such is often called “cartoon physics”, because many old cartoons tended to have people and things behave in a rather Aristotelian manner.)

Work at developing your physical intuition!

Additionally, be forewarned!

This will not be the first point at which you may struggle with gaining an intuitive understanding of a subject in Physics.

While Newtonian Physics matches the real everyday world we experience on a daily basis, it is already known to be invalid, to one degree or another.

The closer fits to reality are:

1. Relativity: both Special and General Relativity (SR & GR); which works from neutrons to the entire Universe.
2. Quantum Mechanics (QM), particularly its most mature form of Quantum Field Theory (QFT); which works for smaller macroscopic “things” down to subatomic “particles”. (QFT includes SR.)

Unfortunately, both are far from our everyday experiences. So both are far from being naturally “intuitive”.

You could actually have a longterm advantage by having to struggle with an intuitive “feel” for physics, even at the Newtonian level!

If you’re interested in physics as a career it may be hard to navigate around your preferences. Classical mechanics is everywhere in physics. If you want be an experimenter or think about anything that’s practical you’ll spend most of your time with electrodynamics. Even as a experimenter any ‘quantum’ will be only small fraction of your time, classical physics dominates your apparatus and that’s something you’ll always deal with. Theoretical physics is a better choice but stay away from anything down to earth like condensed matter or even astro if you don’t like mechanics. You’re probably left with some obscure branch in theoretical physics.

Even in a phd quantum mech class that I took, I remember the prof giving a homework with the harmonic oscillator. The class was perplexed and gave a non-verbal vibe of ‘this is out of the scope of this course, we can’t do that’. The prof responded with: ‘don’t you give me that look, you guys see the oscillator all the time!’.

I don’t think you’ll escape classical mech from theoretical physics either. There is also a quote by famous physicist Sidney Coleman: ‘The career of a young theoretical physicist consists of treating the harmonic oscillator in ever-increasing levels of abstraction’.

Alexie Veronin or more accurately Feynman may be right, introductory classical physics is perhaps too boring. Things get interesting once you go beyond the introductory things. It was in grad school that I for the first time realized that classical mechanics is more interesting than quantum.

Also the most interesting book I’ve ever read was ‘mechanics: from newtons laws to deterministic chaos’ by Florian Scheck. It was almost a decade ago (also with insufficient background - I just completed one year of college!) and can’t give an accurate review . If you really are a physicist that book (especially the later chapters) will change your perception of mechanics as something boring (you might need some advanced math background too).

M.Sc in Physics graduates can pursue their career in various government owned Scientific Research and Development Organizations such as Defense Research and Development Organization (DRDO), Physical Research Laboratory Ahmedabad, Nuclear Science Centre New Delhi, Saha Institute of Nuclear Physics Kolkata, Bhabha Atomic Research Centre (BARC) and Indian Space Research Organization (ISRO). Several other government organizations are also offering various jobs for these graduates. Some of those organizations are listed below.

• Oil and Natural Gas Corporation (ONGC)
• Bharat Heavy Electricals Limited (BHEL)
• National Thermal Power Corporation (NTPC)

These graduates can get into civil service like IAS, IFS and IPS after qualifying the civil service exam conducted by Union Public Service Examination. They can write various government exams like Tax Assistant Exam, Statistical Investigator Exam and Combined Graduate Level Exam to pursue their career in various government departments. They can go for teaching jobs available in government schools or colleges. For getting these jobs, they should qualify either NET or SET exam. They can also pursue their career in the railways by qualifying the exams conducted by Railway Recruitment Board. Those who want to pursue their career in the defense department can write the Combined Defense Services Exams conducted by Union Public Service Commission. M.Sc in Physics graduates can also apply for the job of lab technician available in various public sector organizations.

Read more here: Career after M.Sc in Physics

For kinematics: 1. Picture. 2. Basic equations. 3. Choose origin and axes and *label* them on your drawing. 4. Fill in every variable you know. 5. Look at the equations and see which is easiest to solve. By “basic equations” I mean x = x0 + v0x t + 1/2 ax t^2, vx = v0x + ax t, and the y equations like them. You can get everything done with just those two (or 4, in 2d.) It won’t always be the fastest way but it will work.

For Newton’s laws, do as many easy problems as you can find. Seriously, lots and lots of basic problems, not complex ones while you’re still shaky on the concepts. Get a physics textbook out of the library that has problems rated by difficulty, and do all the level 1 problems.

Good luck!

Countless careers are possible, from toy makers and designers (and learning kits), to working for gov’t agencies like JPL in Pasadena CA, to SpaceX or even Tesla, and more!

The important thing to realize is that your career as a student can be completely different that your career as a professional. As a student, you are [sadly] made to study and test against all other students regardless of your passion. As a professional, you can pave your own way and find success driving down it on your way to work everyday. BTW, you also get to define what success means to you, unlike the rubrics you are used to in school.

All of us at Cerebrum wish you well and hope to hear success stories about you!

As per my understanding may tell you few fields that compromise both the subjects and you can choose any of them as your career for this you have to choose an education path, for example starting from bachelors in either of the subjects then pursuing masters in both subjects.

During my masters i was offered course like biophysics,complex systems which contain both the subjects.

(1)Biophysics: You will apply physics concepts to understand biological events like features of biomolecules,bio-processes and mechanics of bio-systems.

(2)Medical Physics: In this field you will study medical technologies such as radiation therapy, diagnostic imaging, and nuclear medicine.

(3)Computational Biology: It involves use of mathematical and computational techniques to simulate and assess biological data which requires the foundation understanding of mathematics and physics to apply computational techniques.

(4)Biomedical Engineering: Biomedical engineering involves the use of biology and physics both to develop medical devices,medical photography equipment,artificial organs etc.

(5) Quantum Biology: It includes phenomena such as quantum coherence in photosynthesis, use of quantum mechanics in biological processes and people with strong background of quantum mechanics can be at advantage in this field.

(6)Biomechanics: Biomechanics involves the study of mechanical features of biological systems like movement of muscles and joints,the physical characteristics of tissuesand others.

To choose a career that combines both physics and biology you have to go through academics so you can start with a bachelor's degree in either biology or physics and then a master's or Ph.D. in a specialized field that combines the two.

Think in a different way - top down approach - think of problems you would like to be part of. A few examples: space exploration, artificial intelligence or currency - in the case of cryptocurrency wave that is currently happening.

Now that you picked a couple of choices in the upper level - go one step down - for example - space exploration will go through the mechanics of a rocket, the chemistry of the fuel, the problems of life in space, the physics of the trajectory…you now have a bit more of investigation to figure what these topics are all about - by choosing more upper topics, you may find intersections in your interests.

Finally - finding a purpose gives you a chance of more motivation on your career - but you need to build into yourself a positive attitude towards your life in general - despite the environment. Life is an exploration - you know things you are passionate about - and that will be the best compass!

They Study Bridge construction in particular ‘’Tension and compression’’ these elements are always considered in holding up a suspension Bridge as a rigid structure along with other Bridges too. In houses it’s rafter design and since computers are involved in it they pick the best design for the strongest structure and it’s all plotted out on paper life size with saw cuts for the angles to aid in the assembly. This makes it much faster as you see trucks with Rafters going by it’s all been made at a rafter assembly Mill. There are many other aspects to consider in learning structural engineering as well.

Classical mechanics usually refers to the area or branch of physics using principles or conclusions related to notions, concepts and theories elaborated before quantum theory and the theory of relativity.

Below are some additional detailed definitions and explanations.

Classical mechanics is concerned with the set of physical laws describing the motion of bodies under the influence of a system of forces. The study of the motion of bodies is an ancient one, making classical mechanics one of the oldest and largest subjects in science, engineering and technology. It is also known as Newtonian mechanics, though textbook authors often consider Newtonian mechanics, along with Lagrangian mechanics and Hamiltonian mechanics, as the three main formalisms of classical mechanics.

Classical mechanics describes the motion of macroscopic objects, from projectiles to parts of machinery, and astronomical objects, such as spacecraft, planets, stars and galaxies. Within classical mechanics are sub-fields, including those that describe the behavior of solids, liquids and gases. Classical mechanics provides extremely accurate results when studying large objects and speeds not approaching the speed of light. When the objects being examined are sufficiently small, it becomes necessary to introduce the other major sub-field of mechanics: quantum mechanics. This sub-field adjusts the laws of physics of macroscopic objects for the atomic nature of matter by including the wave–particle duality of atoms and molecules. When neither quantum nor classical mechanics apply, such as at the quantum level with high speeds, quantum field theory (QFT) becomes applicable.

The term classical mechanics was coined in the early 20th century. It describes the system of physics started by Isaac Newton and many contemporary 17th century natural philosophers. It is also built upon the earlier astronomical theories of Johannes Kepler, based on the precise observations of Tycho Brahe and the studies of terrestrial projectile motion of Galileo. Since these aspects of physics were developed long before the emergence of quantum physics and relativity, some sources exclude Einstein's theory of relativity from this category. However, a number of modern sources do include relativistic mechanics, which in their view represents classical mechanics in its most developed and accurate form.

Source: Classical mechanics - Wikipedia

Below is an illustration showing the domain of validity of classical mechanics and other areas of physics (image source: File:Physicsdomains.svg - Wikipedia):

Classical mechanics deals with the motion of bodies under the influence of forces or with the equilibrium of bodies when all forces are balanced. The subject may be thought of as the elaboration and application of basic postulates first enunciated by Isaac Newton in his Philosophiae Naturalis Principia Mathematica (1687), commonly known as the Principia. These postulates, called Newton’s laws of motion, are set forth below. They may be used to predict with great precision a wide variety of phenomena ranging from the motion of individual particles to the interactions of highly complex systems. […]

In the framework of modern physics, classical mechanics can be understood to be an approximation arising out of the more profound laws of quantum mechanics and the theory of relativity. However, that view of the subject’s place greatly undervalues its importance in forming the context, language, and intuition of modern science and scientists. Our present-day view of the world and man’s place in it is firmly rooted in classical mechanics. Moreover, many ideas and results of classical mechanics survive and play an important part in the new physics.

Source: mechanics | physics

See also the following related links:

Mechanics - Wikipedia

What Is Classical Mechanics? [LiveScience]

What is classical mechanics?

Definition of Classical Mechanics | Chegg.com